[PATCH v2 0/4] ecdsa KEYCTL_PKEY_QUERY fixes

[PATCH v2 0/4] ecdsa KEYCTL_PKEY_QUERY fixes

[Lukas Wunner]

For ecdsa, KEYCTL_PKEY_QUERY reports nonsensical values for
enc/dec size and (for P521 keys) also the key size.
Second attempt at fixing them.

Changes v1 -> v2:

* New patch [2/4] to introduce DIV_ROUND_UP_POW2(), which avoids
  integer overflows that may occur with DIV_ROUND_UP() (Herbert)

* Amend patch [4/4] to use DIV_ROUND_UP_POW2() (Herbert)

* Amend patch [4/4] to use BITS_PER_BYTE for clarity

Link to v1:

  https://lore.kernel.org/r/cover.1735236227.git.lukas@wunner.de

Lukas Wunner (4):
  crypto: sig - Prepare for algorithms with variable signature size
  crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()
  crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY
  crypto: ecdsa - Fix NIST P521 key size reported by KEYCTL_PKEY_QUERY

 crypto/asymmetric_keys/public_key.c | 22 +++++++++++-----------
 crypto/ecc.c                        |  2 +-
 crypto/ecdsa-p1363.c                |  8 +++++---
 crypto/ecdsa-x962.c                 |  7 ++++---
 crypto/ecdsa.c                      |  2 +-
 crypto/ecrdsa.c                     |  2 +-
 crypto/rsassa-pkcs1.c               |  4 ++--
 crypto/sig.c                        |  9 +++++++--
 crypto/testmgr.c                    |  7 ++++---
 include/crypto/sig.h                |  7 ++++---
 include/linux/math.h                | 12 ++++++++++++
 11 files changed, 52 insertions(+), 30 deletions(-)

-- 
2.43.0

[PATCH v2 1/4] crypto: sig - Prepare for algorithms with variable signature size

[Lukas Wunner]

The callers of crypto_sig_sign() assume that the signature size is
always equivalent to the key size.

This happens to be true for RSA, which is currently the only algorithm
implementing the ->sign() callback.  But it is false e.g. for X9.62
encoded ECDSA signatures because they have variable length.

Prepare for addition of a ->sign() callback to such algorithms by
letting the callback return the signature size (or a negative integer
on error).  When testing the ->sign() callback in test_sig_one(),
use crypto_sig_maxsize() instead of crypto_sig_keysize() to verify that
the test vector's signature does not exceed an algorithm's maximum
signature size.

There has been a relatively recent effort to upstream ECDSA signature
generation support which may benefit from this change:

https://lore.kernel.org/linux-crypto/20220908200036.2034-1-ignat@cloudflare.com/

However the main motivation for this commit is to reduce the number of
crypto_sig_keysize() callers:  This function is about to be changed to
return the size in bits instead of bytes and that will require amending
most callers to divide the return value by 8.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Cc: Ignat Korchagin <ignat@cloudflare.com>
---
 crypto/asymmetric_keys/public_key.c | 9 ++-------
 crypto/rsassa-pkcs1.c               | 2 +-
 crypto/testmgr.c                    | 7 ++++---
 include/crypto/sig.h                | 5 +++--
 4 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index bbd07a9022e6..bf165d321440 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -267,7 +267,6 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
 	struct crypto_sig *sig;
 	char *key, *ptr;
 	bool issig;
-	int ksz;
 	int ret;
 
 	pr_devel("==>%s()\n", __func__);
@@ -302,8 +301,6 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
 			ret = crypto_sig_set_pubkey(sig, key, pkey->keylen);
 		if (ret)
 			goto error_free_tfm;
-
-		ksz = crypto_sig_keysize(sig);
 	} else {
 		tfm = crypto_alloc_akcipher(alg_name, 0, 0);
 		if (IS_ERR(tfm)) {
@@ -317,8 +314,6 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
 			ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
 		if (ret)
 			goto error_free_tfm;
-
-		ksz = crypto_akcipher_maxsize(tfm);
 	}
 
 	ret = -EINVAL;
@@ -347,8 +342,8 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
 		BUG();
 	}
 
-	if (ret == 0)
-		ret = ksz;
+	if (!issig && ret == 0)
+		ret = crypto_akcipher_maxsize(tfm);
 
 error_free_tfm:
 	if (issig)
diff --git a/crypto/rsassa-pkcs1.c b/crypto/rsassa-pkcs1.c
index f68ffd338f48..d01ac75635e0 100644
--- a/crypto/rsassa-pkcs1.c
+++ b/crypto/rsassa-pkcs1.c
@@ -210,7 +210,7 @@ static int rsassa_pkcs1_sign(struct crypto_sig *tfm,
 		memset(dst, 0, pad_len);
 	}
 
-	return 0;
+	return ctx->key_size;
 }
 
 static int rsassa_pkcs1_verify(struct crypto_sig *tfm,
diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index e61490ba4095..b69877db3f33 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -4328,7 +4328,7 @@ static int test_sig_one(struct crypto_sig *tfm, const struct sig_testvec *vecs)
 	if (vecs->public_key_vec)
 		return 0;
 
-	sig_size = crypto_sig_keysize(tfm);
+	sig_size = crypto_sig_maxsize(tfm);
 	if (sig_size < vecs->c_size) {
 		pr_err("alg: sig: invalid maxsize %u\n", sig_size);
 		return -EINVAL;
@@ -4340,13 +4340,14 @@ static int test_sig_one(struct crypto_sig *tfm, const struct sig_testvec *vecs)
 
 	/* Run asymmetric signature generation */
 	err = crypto_sig_sign(tfm, vecs->m, vecs->m_size, sig, sig_size);
-	if (err) {
+	if (err < 0) {
 		pr_err("alg: sig: sign test failed: err %d\n", err);
 		return err;
 	}
 
 	/* Verify that generated signature equals cooked signature */
-	if (memcmp(sig, vecs->c, vecs->c_size) ||
+	if (err != vecs->c_size ||
+	    memcmp(sig, vecs->c, vecs->c_size) ||
 	    memchr_inv(sig + vecs->c_size, 0, sig_size - vecs->c_size)) {
 		pr_err("alg: sig: sign test failed: invalid output\n");
 		hexdump(sig, sig_size);
diff --git a/include/crypto/sig.h b/include/crypto/sig.h
index cff41ad93824..11024708c069 100644
--- a/include/crypto/sig.h
+++ b/include/crypto/sig.h
@@ -23,7 +23,8 @@ struct crypto_sig {
  * struct sig_alg - generic public key signature algorithm
  *
  * @sign:	Function performs a sign operation as defined by public key
- *		algorithm. Optional.
+ *		algorithm. On success, the signature size is returned.
+ *		Optional.
  * @verify:	Function performs a complete verify operation as defined by
  *		public key algorithm, returning verification status. Optional.
  * @set_pub_key: Function invokes the algorithm specific set public key
@@ -186,7 +187,7 @@ static inline unsigned int crypto_sig_maxsize(struct crypto_sig *tfm)
  * @dst:	destination obuffer
  * @dlen:	destination length
  *
- * Return: zero on success; error code in case of error
+ * Return: signature size on success; error code in case of error
  */
 static inline int crypto_sig_sign(struct crypto_sig *tfm,
 				  const void *src, unsigned int slen,
-- 
2.43.0

[PATCH v2 2/4] crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()

[Lukas Wunner]

Herbert notes that DIV_ROUND_UP() may overflow unnecessarily if an ecdsa
implementation's ->key_size() callback returns an unusually large value.
Herbert instead suggests (for a division by 8):

  X / 8 + !!(X & 7)

Based on this formula, introduce a generic DIV_ROUND_UP_POW2() macro and
use it in lieu of DIV_ROUND_UP() for ->key_size() return values.

Additionally, use the macro in ecc_digits_from_bytes(), whose "nbytes"
parameter is a ->key_size() return value in some instances, or a
user-specified ASN.1 length in the case of ecdsa_get_signature_rs().

Link: https://lore.kernel.org/r/Z3iElsILmoSu6FuC@gondor.apana.org.au/
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
Changes v1 -> v2:
* New patch introduced in v2

 crypto/ecc.c         |  2 +-
 crypto/ecdsa-p1363.c |  2 +-
 crypto/ecdsa-x962.c  |  4 ++--
 include/linux/math.h | 12 ++++++++++++
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/crypto/ecc.c b/crypto/ecc.c
index 50ad2d4ed672..6cf9a945fc6c 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -71,7 +71,7 @@ EXPORT_SYMBOL(ecc_get_curve);
 void ecc_digits_from_bytes(const u8 *in, unsigned int nbytes,
 			   u64 *out, unsigned int ndigits)
 {
-	int diff = ndigits - DIV_ROUND_UP(nbytes, sizeof(u64));
+	int diff = ndigits - DIV_ROUND_UP_POW2(nbytes, sizeof(u64));
 	unsigned int o = nbytes & 7;
 	__be64 msd = 0;
 
diff --git a/crypto/ecdsa-p1363.c b/crypto/ecdsa-p1363.c
index eaae7214d69b..4454f1f8f33f 100644
--- a/crypto/ecdsa-p1363.c
+++ b/crypto/ecdsa-p1363.c
@@ -22,7 +22,7 @@ static int ecdsa_p1363_verify(struct crypto_sig *tfm,
 {
 	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
 	unsigned int keylen = crypto_sig_keysize(ctx->child);
-	unsigned int ndigits = DIV_ROUND_UP(keylen, sizeof(u64));
+	unsigned int ndigits = DIV_ROUND_UP_POW2(keylen, sizeof(u64));
 	struct ecdsa_raw_sig sig;
 
 	if (slen != 2 * keylen)
diff --git a/crypto/ecdsa-x962.c b/crypto/ecdsa-x962.c
index 6a77c13e192b..90a04f4b9a2f 100644
--- a/crypto/ecdsa-x962.c
+++ b/crypto/ecdsa-x962.c
@@ -81,8 +81,8 @@ static int ecdsa_x962_verify(struct crypto_sig *tfm,
 	struct ecdsa_x962_signature_ctx sig_ctx;
 	int err;
 
-	sig_ctx.ndigits = DIV_ROUND_UP(crypto_sig_keysize(ctx->child),
-				       sizeof(u64));
+	sig_ctx.ndigits = DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
+					    sizeof(u64));
 
 	err = asn1_ber_decoder(&ecdsasignature_decoder, &sig_ctx, src, slen);
 	if (err < 0)
diff --git a/include/linux/math.h b/include/linux/math.h
index f5f18dc3616b..0198c92cbe3e 100644
--- a/include/linux/math.h
+++ b/include/linux/math.h
@@ -34,6 +34,18 @@
  */
 #define round_down(x, y) ((x) & ~__round_mask(x, y))
 
+/**
+ * DIV_ROUND_UP_POW2 - divide and round up
+ * @n: numerator
+ * @d: denominator (must be a power of 2)
+ *
+ * Divides @n by @d and rounds up to next multiple of @d (which must be a power
+ * of 2). Avoids integer overflows that may occur with __KERNEL_DIV_ROUND_UP().
+ * Performance is roughly equivalent to __KERNEL_DIV_ROUND_UP().
+ */
+#define DIV_ROUND_UP_POW2(n, d) \
+	((n) / (d) + !!((n) & ((d) - 1)))
+
 #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
 
 #define DIV_ROUND_DOWN_ULL(ll, d) \
-- 
2.43.0

Re: [PATCH v2 2/4] crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()

[Lukas Wunner]

On Sun, Feb 02, 2025 at 08:00:52PM +0100, Lukas Wunner wrote:
> Herbert notes that DIV_ROUND_UP() may overflow unnecessarily if an ecdsa
> implementation's ->key_size() callback returns an unusually large value.
> Herbert instead suggests (for a division by 8):
> 
>   X / 8 + !!(X & 7)
> 
> Based on this formula, introduce a generic DIV_ROUND_UP_POW2() macro and
> use it in lieu of DIV_ROUND_UP() for ->key_size() return values.

FWIW, I've explored amending DIV_ROUND_UP() to automatically invoke
DIV_ROUND_UP_POW2() for constant power-of-2 divisors, like this:

#define DIV_ROUND_UP(n, d)						\
	(__builtin_constant_p(d) && is_power_of_2(d)			\
		? DIV_ROUND_UP_POW2(n, d)				\
		: __KERNEL_DIV_ROUND_UP(n, d))

Unfortunately gcc then complains about arrays sized with DIV_ROUND_UP().
It's possible to work around that by changing those occurrences to
__KERNEL_DIV_ROUND_UP().

The resulting patch is below.  It can be applied on top of this series.
I think it's somewhat intrusive and thus unpleasant, so I decided against
this approach for now and instead kept usage of DIV_ROUND_UP_POW2() local
to ecdsa.

But I'm considering submitting the below patch as an RFC to the
linux-hardening folks.  At Plumbers they held an Integer Overflow
Prevention BoF so this might be of interest to them:
https://lpc.events/event/18/contributions/1872/

Thanks,

Lukas

-- >8 --
Subject: [PATCH] treewide: Harden against integer overflows in DIV_ROUND_UP()

Herbert Xu notes that DIV_ROUND_UP() may overflow unnecessarily and
instead suggests (for a division by 8):

  X / 8 + !!(X & 7)

Based on this formula, a generic DIV_ROUND_UP_POW2() macro has just been
introduced.  Use it in DIV_ROUND_UP() for any constant divisor which is
a power of 2.

Convert all occurrences of DIV_ROUND_UP_POW2() in the crypto subsystem
to DIV_ROUND_UP(), which will internally expand to DIV_ROUND_UP_POW2().

Unfortunately wherever DIV_ROUND_UP() is used to size an array, gcc will
now raise errors such as:

  include/linux/tcp.h:91:17: error: variably modified 'val' at file scope
  __le64  val[DIV_ROUND_UP(TCP_FASTOPEN_COOKIE_MAX, sizeof(u64))];

It seems gcc does not lower the more complex DIV_ROUND_UP() macro before
determining whether an array is variably sized.  Work around by using
__KERNEL_DIV_ROUND_UP() in lieu of DIV_ROUND_UP() wherever it's used
to size arrays.  Same for initializers of static variables.

Link: https://lore.kernel.org/r/Z3iElsILmoSu6FuC@gondor.apana.org.au/
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 arch/arm/include/asm/kprobes.h                |  3 +-
 arch/arm64/include/asm/fixmap.h               |  3 +-
 arch/arm64/kernel/ptrace.c                    | 14 ++++----
 arch/loongarch/include/asm/bootinfo.h         |  2 +-
 arch/x86/kernel/espfix_64.c                   |  3 +-
 arch/x86/kvm/hyperv.c                         |  3 +-
 crypto/ecc.c                                  |  2 +-
 crypto/ecdsa-p1363.c                          |  9 +++--
 crypto/ecdsa-x962.c                           |  7 ++--
 crypto/sig.c                                  |  2 +-
 drivers/accel/qaic/sahara.c                   |  5 +--
 drivers/cdx/controller/mcdi.h                 |  3 +-
 drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h  |  2 +-
 drivers/crypto/allwinner/sun8i-ss/sun8i-ss.h  |  2 +-
 drivers/crypto/sa2ul.h                        |  3 +-
 drivers/firewire/ohci.c                       |  5 +--
 drivers/fpga/ice40-spi.c                      |  2 +-
 drivers/fpga/intel-m10-bmc-sec-update.c       |  2 +-
 drivers/gpio/gpio-graniterapids.c             |  2 +-
 drivers/gpio/gpio-stmpe.c                     |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu.h           |  2 +-
 drivers/gpu/drm/i915/gt/intel_sseu.h          |  2 +-
 drivers/gpu/drm/i915/i915_perf_types.h        |  2 +-
 drivers/gpu/drm/imagination/pvr_fw_mips.h     |  2 +-
 drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.h |  2 +-
 drivers/gpu/drm/tests/drm_framebuffer_test.c  | 34 +++++++++++--------
 drivers/input/rmi4/rmi_f30.c                  |  2 +-
 drivers/input/rmi4/rmi_f3a.c                  |  3 +-
 drivers/irqchip/irq-gic.c                     |  8 ++---
 drivers/irqchip/irq-mst-intc.c                |  2 +-
 drivers/media/firewire/firedtv-fw.c           |  3 +-
 drivers/media/pci/intel/ipu3/ipu3-cio2.c      |  4 +--
 drivers/media/pci/pt3/pt3.h                   |  2 +-
 drivers/media/platform/nxp/dw100/dw100.c      |  4 +--
 drivers/mfd/twl4030-irq.c                     |  4 +--
 drivers/net/ethernet/chelsio/cxgb4/t4_hw.c    |  5 ++-
 drivers/net/ethernet/chelsio/cxgb4vf/sge.c    |  3 +-
 drivers/net/ethernet/cisco/enic/vnic_rq.h     |  2 +-
 drivers/net/ethernet/cisco/enic/vnic_wq.h     |  2 +-
 drivers/net/ethernet/google/gve/gve.h         |  3 +-
 .../hisilicon/hns3/hns3pf/hclge_main.h        |  2 +-
 drivers/net/ethernet/meta/fbnic/fbnic_csr.h   |  4 +--
 drivers/net/ethernet/qlogic/qed/qed_debug.c   |  2 +-
 drivers/net/ethernet/sfc/falcon/falcon.c      |  2 +-
 drivers/net/ethernet/sfc/mcdi.h               |  4 +--
 drivers/net/ethernet/sfc/siena/mcdi.h         |  4 +--
 drivers/net/ethernet/sfc/siena/ptp.c          |  2 +-
 drivers/net/ethernet/ti/cpsw_ale.h            |  2 +-
 drivers/net/wireless/mediatek/mt76/mt76.h     |  4 +--
 .../wireless/mediatek/mt76/mt76x0/eeprom.c    |  2 +-
 drivers/perf/arm-cmn.c                        |  2 +-
 drivers/scsi/fnic/vnic_rq.h                   |  2 +-
 drivers/scsi/fnic/vnic_wq.h                   |  2 +-
 drivers/scsi/snic/vnic_wq.h                   |  4 +--
 drivers/xen/xenbus/xenbus_client.c            |  3 +-
 fs/ceph/crypto.h                              |  2 +-
 fs/ceph/mds_client.c                          |  3 +-
 fs/erofs/decompressor.c                       |  6 ++--
 fs/exfat/exfat_fs.h                           |  5 +--
 fs/nfs/nfs42proc.c                            |  2 +-
 fs/nfs/nfs4proc.c                             |  2 +-
 fs/nfs/nfs4session.h                          |  2 +-
 fs/orangefs/orangefs-bufmap.c                 |  2 +-
 include/crypto/internal/ecc.h                 |  2 +-
 include/linux/can/length.h                    |  5 ++-
 include/linux/gpio/gpio-nomadik.h             |  2 +-
 include/linux/math.h                          |  6 +++-
 include/linux/mmzone.h                        |  3 +-
 include/linux/nfs4.h                          |  3 +-
 include/linux/rcu_node_tree.h                 | 12 +++----
 include/linux/tcp.h                           |  2 +-
 include/net/cfg80211.h                        |  2 +-
 kernel/events/core.c                          |  2 +-
 kernel/power/swap.c                           |  4 +--
 kernel/rcu/tasks.h                            |  2 +-
 lib/bch.c                                     |  2 +-
 lib/test_bitmap.c                             |  7 ++--
 mm/zsmalloc.c                                 |  5 +--
 net/ethtool/bitset.c                          |  2 +-
 net/ethtool/common.h                          |  2 +-
 net/ethtool/ioctl.c                           |  2 +-
 net/mac80211/airtime.c                        |  2 +-
 net/mac80211/rc80211_minstrel_ht.c            |  2 +-
 security/selinux/ss/sidtab.h                  |  5 +--
 sound/usb/misc/ua101.c                        |  2 +-
 85 files changed, 165 insertions(+), 143 deletions(-)

diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h
index 5b8dbf1b0be4..5ea8ba6246f4 100644
--- a/arch/arm/include/asm/kprobes.h
+++ b/arch/arm/include/asm/kprobes.h
@@ -63,7 +63,8 @@ struct arch_optimized_insn {
 	 * copy of the original instructions.
 	 * Different from x86, ARM kprobe_opcode_t is u32.
 	 */
-#define MAX_COPIED_INSN	DIV_ROUND_UP(RELATIVEJUMP_SIZE, sizeof(kprobe_opcode_t))
+#define MAX_COPIED_INSN	__KERNEL_DIV_ROUND_UP(RELATIVEJUMP_SIZE, \
+					      sizeof(kprobe_opcode_t))
 	kprobe_opcode_t copied_insn[MAX_COPIED_INSN];
 	/* detour code buffer */
 	kprobe_opcode_t *insn;
diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
index 87e307804b99..7043733dc240 100644
--- a/arch/arm64/include/asm/fixmap.h
+++ b/arch/arm64/include/asm/fixmap.h
@@ -43,7 +43,8 @@ enum fixed_addresses {
 	 * whether it crosses any page boundary.
 	 */
 	FIX_FDT_END,
-	FIX_FDT = FIX_FDT_END + DIV_ROUND_UP(MAX_FDT_SIZE, PAGE_SIZE) + 1,
+	FIX_FDT = FIX_FDT_END + __KERNEL_DIV_ROUND_UP(MAX_FDT_SIZE, PAGE_SIZE)
+		  + 1,
 
 	FIX_EARLYCON_MEM_BASE,
 	FIX_TEXT_POKE0,
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index f79b0d5f71ac..48c0eae2afbd 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -1654,9 +1654,9 @@ static const struct user_regset aarch64_regsets[] = {
 #ifdef CONFIG_ARM64_SVE
 	[REGSET_SVE] = { /* Scalable Vector Extension */
 		.core_note_type = NT_ARM_SVE,
-		.n = DIV_ROUND_UP(SVE_PT_SIZE(ARCH_SVE_VQ_MAX,
-					      SVE_PT_REGS_SVE),
-				  SVE_VQ_BYTES),
+		.n = __KERNEL_DIV_ROUND_UP(SVE_PT_SIZE(ARCH_SVE_VQ_MAX,
+						       SVE_PT_REGS_SVE),
+					   SVE_VQ_BYTES),
 		.size = SVE_VQ_BYTES,
 		.align = SVE_VQ_BYTES,
 		.regset_get = sve_get,
@@ -1666,8 +1666,9 @@ static const struct user_regset aarch64_regsets[] = {
 #ifdef CONFIG_ARM64_SME
 	[REGSET_SSVE] = { /* Streaming mode SVE */
 		.core_note_type = NT_ARM_SSVE,
-		.n = DIV_ROUND_UP(SVE_PT_SIZE(SME_VQ_MAX, SVE_PT_REGS_SVE),
-				  SVE_VQ_BYTES),
+		.n = __KERNEL_DIV_ROUND_UP(SVE_PT_SIZE(SME_VQ_MAX,
+						       SVE_PT_REGS_SVE),
+					   SVE_VQ_BYTES),
 		.size = SVE_VQ_BYTES,
 		.align = SVE_VQ_BYTES,
 		.regset_get = ssve_get,
@@ -1683,7 +1684,8 @@ static const struct user_regset aarch64_regsets[] = {
 		 * registers. These values aren't exposed to
 		 * userspace.
 		 */
-		.n = DIV_ROUND_UP(ZA_PT_SIZE(SME_VQ_MAX), SVE_VQ_BYTES),
+		.n = __KERNEL_DIV_ROUND_UP(ZA_PT_SIZE(SME_VQ_MAX),
+					   SVE_VQ_BYTES),
 		.size = SVE_VQ_BYTES,
 		.align = SVE_VQ_BYTES,
 		.regset_get = za_get,
diff --git a/arch/loongarch/include/asm/bootinfo.h b/arch/loongarch/include/asm/bootinfo.h
index 7657e016233f..8b7846bdd985 100644
--- a/arch/loongarch/include/asm/bootinfo.h
+++ b/arch/loongarch/include/asm/bootinfo.h
@@ -24,7 +24,7 @@ struct loongson_board_info {
 	const char *board_vendor;
 };
 
-#define NR_WORDS DIV_ROUND_UP(NR_CPUS, BITS_PER_LONG)
+#define NR_WORDS BITS_TO_LONGS(NR_CPUS)
 
 /*
  * The "core" of cores_per_node and cores_per_package stands for a
diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c
index 6726e0473d0b..4515817cec09 100644
--- a/arch/x86/kernel/espfix_64.c
+++ b/arch/x86/kernel/espfix_64.c
@@ -59,7 +59,8 @@ DEFINE_PER_CPU_READ_MOSTLY(unsigned long, espfix_waddr);
 static DEFINE_MUTEX(espfix_init_mutex);
 
 /* Page allocation bitmap - each page serves ESPFIX_STACKS_PER_PAGE CPUs */
-#define ESPFIX_MAX_PAGES  DIV_ROUND_UP(CONFIG_NR_CPUS, ESPFIX_STACKS_PER_PAGE)
+#define ESPFIX_MAX_PAGES	\
+	__KERNEL_DIV_ROUND_UP(CONFIG_NR_CPUS, ESPFIX_STACKS_PER_PAGE)
 static void *espfix_pages[ESPFIX_MAX_PAGES];
 
 static __page_aligned_bss pud_t espfix_pud_page[PTRS_PER_PUD]
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 6a6dd5a84f22..771c97953d38 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -42,7 +42,8 @@
 #include "irq.h"
 #include "fpu.h"
 
-#define KVM_HV_MAX_SPARSE_VCPU_SET_BITS DIV_ROUND_UP(KVM_MAX_VCPUS, HV_VCPUS_PER_SPARSE_BANK)
+#define KVM_HV_MAX_SPARSE_VCPU_SET_BITS \
+	__KERNEL_DIV_ROUND_UP(KVM_MAX_VCPUS, HV_VCPUS_PER_SPARSE_BANK)
 
 /*
  * As per Hyper-V TLFS, extended hypercalls start from 0x8001
diff --git a/crypto/ecc.c b/crypto/ecc.c
index 6cf9a945fc6c..50ad2d4ed672 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -71,7 +71,7 @@ EXPORT_SYMBOL(ecc_get_curve);
 void ecc_digits_from_bytes(const u8 *in, unsigned int nbytes,
 			   u64 *out, unsigned int ndigits)
 {
-	int diff = ndigits - DIV_ROUND_UP_POW2(nbytes, sizeof(u64));
+	int diff = ndigits - DIV_ROUND_UP(nbytes, sizeof(u64));
 	unsigned int o = nbytes & 7;
 	__be64 msd = 0;
 
diff --git a/crypto/ecdsa-p1363.c b/crypto/ecdsa-p1363.c
index e0c55c64711c..d668d816d16c 100644
--- a/crypto/ecdsa-p1363.c
+++ b/crypto/ecdsa-p1363.c
@@ -21,9 +21,9 @@ static int ecdsa_p1363_verify(struct crypto_sig *tfm,
 			      const void *digest, unsigned int dlen)
 {
 	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
-	unsigned int keylen = DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
-						BITS_PER_BYTE);
-	unsigned int ndigits = DIV_ROUND_UP_POW2(keylen, sizeof(u64));
+	unsigned int keylen = DIV_ROUND_UP(crypto_sig_keysize(ctx->child),
+					   BITS_PER_BYTE);
+	unsigned int ndigits = DIV_ROUND_UP(keylen, sizeof(u64));
 	struct ecdsa_raw_sig sig;
 
 	if (slen != 2 * keylen)
@@ -46,8 +46,7 @@ static unsigned int ecdsa_p1363_max_size(struct crypto_sig *tfm)
 {
 	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
 
-	return 2 * DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
-				     BITS_PER_BYTE);
+	return 2 * DIV_ROUND_UP(crypto_sig_keysize(ctx->child), BITS_PER_BYTE);
 }
 
 static unsigned int ecdsa_p1363_digest_size(struct crypto_sig *tfm)
diff --git a/crypto/ecdsa-x962.c b/crypto/ecdsa-x962.c
index ee71594d10a0..73d4f3e2e5a6 100644
--- a/crypto/ecdsa-x962.c
+++ b/crypto/ecdsa-x962.c
@@ -81,8 +81,8 @@ static int ecdsa_x962_verify(struct crypto_sig *tfm,
 	struct ecdsa_x962_signature_ctx sig_ctx;
 	int err;
 
-	sig_ctx.ndigits = DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
-					    sizeof(u64) * BITS_PER_BYTE);
+	sig_ctx.ndigits = DIV_ROUND_UP(crypto_sig_keysize(ctx->child),
+				       sizeof(u64) * BITS_PER_BYTE);
 
 	err = asn1_ber_decoder(&ecdsasignature_decoder, &sig_ctx, src, slen);
 	if (err < 0)
@@ -103,8 +103,7 @@ static unsigned int ecdsa_x962_max_size(struct crypto_sig *tfm)
 {
 	struct ecdsa_x962_ctx *ctx = crypto_sig_ctx(tfm);
 	struct sig_alg *alg = crypto_sig_alg(ctx->child);
-	int slen = DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
-				     BITS_PER_BYTE);
+	int slen = DIV_ROUND_UP(crypto_sig_keysize(ctx->child), BITS_PER_BYTE);
 
 	/*
 	 * Verify takes ECDSA-Sig-Value (described in RFC 5480) as input,
diff --git a/crypto/sig.c b/crypto/sig.c
index 53a3dd6fbe3f..c0b8017b40c3 100644
--- a/crypto/sig.c
+++ b/crypto/sig.c
@@ -104,7 +104,7 @@ static int sig_default_set_key(struct crypto_sig *tfm,
 
 static unsigned int sig_default_size(struct crypto_sig *tfm)
 {
-	return DIV_ROUND_UP_POW2(crypto_sig_keysize(tfm), BITS_PER_BYTE);
+	return DIV_ROUND_UP(crypto_sig_keysize(tfm), BITS_PER_BYTE);
 }
 
 static int sig_prepare_alg(struct sig_alg *alg)
diff --git a/drivers/accel/qaic/sahara.c b/drivers/accel/qaic/sahara.c
index 21d58aed0deb..98fef467897f 100644
--- a/drivers/accel/qaic/sahara.c
+++ b/drivers/accel/qaic/sahara.c
@@ -39,8 +39,9 @@
 #define SAHARA_PACKET_MAX_SIZE		0xffffU /* MHI_MAX_MTU */
 #define SAHARA_TRANSFER_MAX_SIZE	0x80000
 #define SAHARA_READ_MAX_SIZE		0xfff0U /* Avoid unaligned requests */
-#define SAHARA_NUM_TX_BUF		DIV_ROUND_UP(SAHARA_TRANSFER_MAX_SIZE,\
-							SAHARA_PACKET_MAX_SIZE)
+#define SAHARA_NUM_TX_BUF		__KERNEL_DIV_ROUND_UP(		      \
+						    SAHARA_TRANSFER_MAX_SIZE, \
+						    SAHARA_PACKET_MAX_SIZE)
 #define SAHARA_IMAGE_ID_NONE		U32_MAX
 
 #define SAHARA_VERSION			2
diff --git a/drivers/cdx/controller/mcdi.h b/drivers/cdx/controller/mcdi.h
index 54a65e9760ae..574f1e358107 100644
--- a/drivers/cdx/controller/mcdi.h
+++ b/drivers/cdx/controller/mcdi.h
@@ -204,7 +204,8 @@ int cdx_mcdi_wait_for_quiescence(struct cdx_mcdi *cdx,
  * are appropriately aligned, but 64-bit fields are only
  * 32-bit-aligned.
  */
-#define MCDI_DECLARE_BUF(_name, _len) struct cdx_dword _name[DIV_ROUND_UP(_len, 4)] = {{0}}
+#define MCDI_DECLARE_BUF(_name, _len)					\
+	struct cdx_dword _name[__KERNEL_DIV_ROUND_UP(_len, 4)] = {{0}}
 #define _MCDI_PTR(_buf, _offset)					\
 	((u8 *)(_buf) + (_offset))
 #define MCDI_PTR(_buf, _field)						\
diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
index 3b5c2af013d0..0be685af435d 100644
--- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
+++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
@@ -97,7 +97,7 @@
 #define ESR_D1	5
 
 #define PRNG_DATA_SIZE (160 / 8)
-#define PRNG_SEED_SIZE DIV_ROUND_UP(175, 8)
+#define PRNG_SEED_SIZE __KERNEL_DIV_ROUND_UP(175, 8)
 #define PRNG_LD BIT(17)
 
 #define CE_DIE_ID_SHIFT	16
diff --git a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss.h b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss.h
index ae66eb45fb24..7cd10b176591 100644
--- a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss.h
+++ b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss.h
@@ -80,7 +80,7 @@
 #define SS_DIE_ID_MASK	0x07
 
 #define PRNG_DATA_SIZE (160 / 8)
-#define PRNG_SEED_SIZE DIV_ROUND_UP(175, 8)
+#define PRNG_SEED_SIZE __KERNEL_DIV_ROUND_UP(175, 8)
 
 #define MAX_PAD_SIZE 4096
 
diff --git a/drivers/crypto/sa2ul.h b/drivers/crypto/sa2ul.h
index 12c17a68d350..94c53d204e6c 100644
--- a/drivers/crypto/sa2ul.h
+++ b/drivers/crypto/sa2ul.h
@@ -202,8 +202,7 @@ struct sa_crypto_data {
 	u16		sc_id_start;
 	u16		sc_id_end;
 	u16		sc_id;
-	unsigned long	ctx_bm[DIV_ROUND_UP(SA_MAX_NUM_CTX,
-				BITS_PER_LONG)];
+	unsigned long	ctx_bm[BITS_TO_LONGS(SA_MAX_NUM_CTX)];
 	struct sa_tfm_ctx	*ctx;
 	struct dma_chan		*dma_rx1;
 	struct dma_chan		*dma_rx2;
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index edaedd156a6d..ca13e7d232db 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -84,13 +84,14 @@ struct descriptor {
 #define CONTEXT_MATCH(regs)	((regs) + 16)
 
 #define AR_BUFFER_SIZE	(32*1024)
-#define AR_BUFFERS_MIN	DIV_ROUND_UP(AR_BUFFER_SIZE, PAGE_SIZE)
+#define AR_BUFFERS_MIN	__KERNEL_DIV_ROUND_UP(AR_BUFFER_SIZE, PAGE_SIZE)
 /* we need at least two pages for proper list management */
 #define AR_BUFFERS	(AR_BUFFERS_MIN >= 2 ? AR_BUFFERS_MIN : 2)
 
 #define MAX_ASYNC_PAYLOAD	4096
 #define MAX_AR_PACKET_SIZE	(16 + MAX_ASYNC_PAYLOAD + 4)
-#define AR_WRAPAROUND_PAGES	DIV_ROUND_UP(MAX_AR_PACKET_SIZE, PAGE_SIZE)
+#define AR_WRAPAROUND_PAGES	__KERNEL_DIV_ROUND_UP(MAX_AR_PACKET_SIZE, \
+						      PAGE_SIZE)
 
 struct ar_context {
 	struct fw_ohci *ohci;
diff --git a/drivers/fpga/ice40-spi.c b/drivers/fpga/ice40-spi.c
index 62c30266130d..3698fd0e5d4f 100644
--- a/drivers/fpga/ice40-spi.c
+++ b/drivers/fpga/ice40-spi.c
@@ -21,7 +21,7 @@
 #define ICE40_SPI_RESET_DELAY 1 /* us (>200ns) */
 #define ICE40_SPI_HOUSEKEEPING_DELAY 1200 /* us */
 
-#define ICE40_SPI_NUM_ACTIVATION_BYTES DIV_ROUND_UP(49, 8)
+#define ICE40_SPI_NUM_ACTIVATION_BYTES __KERNEL_DIV_ROUND_UP(49, 8)
 
 struct ice40_fpga_priv {
 	struct spi_device *dev;
diff --git a/drivers/fpga/intel-m10-bmc-sec-update.c b/drivers/fpga/intel-m10-bmc-sec-update.c
index 10f678b9ed36..9ab58c35ede3 100644
--- a/drivers/fpga/intel-m10-bmc-sec-update.c
+++ b/drivers/fpga/intel-m10-bmc-sec-update.c
@@ -160,7 +160,7 @@ DEVICE_ATTR_SEC_REH_RO(sr);
 DEVICE_ATTR_SEC_REH_RO(pr);
 
 #define CSK_BIT_LEN		128U
-#define CSK_32ARRAY_SIZE	DIV_ROUND_UP(CSK_BIT_LEN, 32)
+#define CSK_32ARRAY_SIZE	__KERNEL_DIV_ROUND_UP(CSK_BIT_LEN, 32)
 
 static ssize_t
 show_canceled_csk(struct device *dev, u32 addr, char *buf)
diff --git a/drivers/gpio/gpio-graniterapids.c b/drivers/gpio/gpio-graniterapids.c
index ad6a045fd3d2..98eb705d7f05 100644
--- a/drivers/gpio/gpio-graniterapids.c
+++ b/drivers/gpio/gpio-graniterapids.c
@@ -30,7 +30,7 @@
 
 #define GNR_NUM_PINS 128
 #define GNR_PINS_PER_REG 32
-#define GNR_NUM_REGS DIV_ROUND_UP(GNR_NUM_PINS, GNR_PINS_PER_REG)
+#define GNR_NUM_REGS __KERNEL_DIV_ROUND_UP(GNR_NUM_PINS, GNR_PINS_PER_REG)
 
 #define GNR_CFG_PADBAR		0x00
 #define GNR_CFG_LOCK_OFFSET	0x04
diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
index 75a3633ceddb..f820e98a87be 100644
--- a/drivers/gpio/gpio-stmpe.c
+++ b/drivers/gpio/gpio-stmpe.c
@@ -381,7 +381,7 @@ static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
 	struct stmpe *stmpe = stmpe_gpio->stmpe;
 	u8 statmsbreg;
 	int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
-	u8 status[DIV_ROUND_UP(MAX_GPIOS, 8)];
+	u8 status[__KERNEL_DIV_ROUND_UP(MAX_GPIOS, 8)];
 	int ret;
 	int i;
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 69895fccb474..5fe7464d340a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -516,7 +516,7 @@ struct amdgpu_wb {
 	volatile uint32_t	*wb;
 	uint64_t		gpu_addr;
 	u32			num_wb;	/* Number of wb slots actually reserved for amdgpu. */
-	unsigned long		used[DIV_ROUND_UP(AMDGPU_MAX_WB, BITS_PER_LONG)];
+	unsigned long		used[BITS_TO_LONGS(AMDGPU_MAX_WB)];
 	spinlock_t		lock;
 };
 
diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.h b/drivers/gpu/drm/i915/gt/intel_sseu.h
index d7e8c374f153..c653805b32e2 100644
--- a/drivers/gpu/drm/i915/gt/intel_sseu.h
+++ b/drivers/gpu/drm/i915/gt/intel_sseu.h
@@ -45,7 +45,7 @@ struct drm_printer;
 #define GEN_SS_MASK_SIZE		SSEU_MAX(I915_MAX_SS_FUSE_BITS, \
 						 GEN_MAX_HSW_SLICES * GEN_MAX_SS_PER_HSW_SLICE)
 
-#define GEN_SSEU_STRIDE(max_entries)	DIV_ROUND_UP(max_entries, BITS_PER_BYTE)
+#define GEN_SSEU_STRIDE(max_entries)	BITS_TO_BYTES(max_entries)
 #define GEN_MAX_SUBSLICE_STRIDE		GEN_SSEU_STRIDE(GEN_SS_MASK_SIZE)
 #define GEN_MAX_EU_STRIDE		GEN_SSEU_STRIDE(GEN_MAX_EUS_PER_SS)
 
diff --git a/drivers/gpu/drm/i915/i915_perf_types.h b/drivers/gpu/drm/i915/i915_perf_types.h
index 39fb6ce4a7ef..ba02c7c64bfb 100644
--- a/drivers/gpu/drm/i915/i915_perf_types.h
+++ b/drivers/gpu/drm/i915/i915_perf_types.h
@@ -502,7 +502,7 @@ struct i915_perf {
 	 * Use a format mask to store the supported formats
 	 * for a platform.
 	 */
-#define FORMAT_MASK_SIZE DIV_ROUND_UP(I915_OA_FORMAT_MAX - 1, BITS_PER_LONG)
+#define FORMAT_MASK_SIZE BITS_TO_LONGS(I915_OA_FORMAT_MAX - 1)
 	unsigned long format_mask[FORMAT_MASK_SIZE];
 
 	atomic64_t noa_programming_delay;
diff --git a/drivers/gpu/drm/imagination/pvr_fw_mips.h b/drivers/gpu/drm/imagination/pvr_fw_mips.h
index a0c5c41c8aa2..e6a17989bd1b 100644
--- a/drivers/gpu/drm/imagination/pvr_fw_mips.h
+++ b/drivers/gpu/drm/imagination/pvr_fw_mips.h
@@ -13,7 +13,7 @@
 /* Forward declaration from pvr_gem.h. */
 struct pvr_gem_object;
 
-#define PVR_MIPS_PT_PAGE_COUNT DIV_ROUND_UP(ROGUE_MIPSFW_MAX_NUM_PAGETABLE_PAGES * ROGUE_MIPSFW_PAGE_SIZE_4K, PAGE_SIZE)
+#define PVR_MIPS_PT_PAGE_COUNT __KERNEL_DIV_ROUND_UP(ROGUE_MIPSFW_MAX_NUM_PAGETABLE_PAGES * ROGUE_MIPSFW_PAGE_SIZE_4K, PAGE_SIZE)
 
 /**
  * struct pvr_fw_mips_data - MIPS-specific data
diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.h b/drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.h
index 5cfa2bb7ad93..c693f34ee52e 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.h
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.h
@@ -89,7 +89,7 @@ struct rcar_du_device_info {
 };
 
 #define RCAR_DU_MAX_CRTCS		4
-#define RCAR_DU_MAX_GROUPS		DIV_ROUND_UP(RCAR_DU_MAX_CRTCS, 2)
+#define RCAR_DU_MAX_GROUPS		__KERNEL_DIV_ROUND_UP(RCAR_DU_MAX_CRTCS, 2)
 #define RCAR_DU_MAX_VSPS		4
 #define RCAR_DU_MAX_LVDS		2
 #define RCAR_DU_MAX_DSI			2
diff --git a/drivers/gpu/drm/tests/drm_framebuffer_test.c b/drivers/gpu/drm/tests/drm_framebuffer_test.c
index 6ea04cc8f324..9c8b6a7d6dbc 100644
--- a/drivers/gpu/drm/tests/drm_framebuffer_test.c
+++ b/drivers/gpu/drm/tests/drm_framebuffer_test.c
@@ -215,35 +215,36 @@ static const struct drm_framebuffer_test drm_framebuffer_create_cases[] = {
 },
 { .buffer_created = 1, .name = "YVU420 Max sizes",
 	.cmd = { .width = MAX_WIDTH, .height = MAX_HEIGHT, .pixel_format = DRM_FORMAT_YVU420,
-		 .handles = { 1, 1, 1 }, .pitches = { MAX_WIDTH, DIV_ROUND_UP(MAX_WIDTH, 2),
-						      DIV_ROUND_UP(MAX_WIDTH, 2) },
+		 .handles = { 1, 1, 1 }, .pitches = { MAX_WIDTH, __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2),
+						      __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) },
 	}
 },
 { .buffer_created = 0, .name = "YVU420 Invalid pitch",
 	.cmd = { .width = MAX_WIDTH, .height = MAX_HEIGHT, .pixel_format = DRM_FORMAT_YVU420,
-		 .handles = { 1, 1, 1 }, .pitches = { MAX_WIDTH, DIV_ROUND_UP(MAX_WIDTH, 2) - 1,
-						      DIV_ROUND_UP(MAX_WIDTH, 2) },
+		 .handles = { 1, 1, 1 }, .pitches = { MAX_WIDTH, __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) - 1,
+						      __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) },
 	}
 },
 { .buffer_created = 1, .name = "YVU420 Different pitches",
 	.cmd = { .width = MAX_WIDTH, .height = MAX_HEIGHT, .pixel_format = DRM_FORMAT_YVU420,
-		 .handles = { 1, 1, 1 }, .pitches = { MAX_WIDTH, DIV_ROUND_UP(MAX_WIDTH, 2) + 1,
-						      DIV_ROUND_UP(MAX_WIDTH, 2) + 7 },
+		 .handles = { 1, 1, 1 }, .pitches = { MAX_WIDTH, __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) + 1,
+						      __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) + 7 },
 	}
 },
 { .buffer_created = 1, .name = "YVU420 Different buffer offsets/pitches",
 	.cmd = { .width = MAX_WIDTH, .height = MAX_HEIGHT, .pixel_format = DRM_FORMAT_YVU420,
 		 .handles = { 1, 1, 1 }, .offsets = { MAX_WIDTH, MAX_WIDTH  +
 			 MAX_WIDTH * MAX_HEIGHT, MAX_WIDTH  + 2 * MAX_WIDTH * MAX_HEIGHT },
-		 .pitches = { MAX_WIDTH, DIV_ROUND_UP(MAX_WIDTH, 2) + 1,
-			 DIV_ROUND_UP(MAX_WIDTH, 2) + 7 },
+		 .pitches = { MAX_WIDTH, __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) + 1,
+			 __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) + 7 },
 	}
 },
 { .buffer_created = 0,
 	.name = "YVU420 Modifier set just for plane 0, without DRM_MODE_FB_MODIFIERS",
 	.cmd = { .width = MAX_WIDTH, .height = MAX_HEIGHT, .pixel_format = DRM_FORMAT_YVU420,
 		 .handles = { 1, 1, 1 }, .modifier = { AFBC_FORMAT_MOD_SPARSE, 0, 0 },
-		 .pitches = { MAX_WIDTH, DIV_ROUND_UP(MAX_WIDTH, 2), DIV_ROUND_UP(MAX_WIDTH, 2) },
+		 .pitches = { MAX_WIDTH, __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2),
+			      __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) },
 	}
 },
 { .buffer_created = 0,
@@ -251,7 +252,8 @@ static const struct drm_framebuffer_test drm_framebuffer_create_cases[] = {
 	.cmd = { .width = MAX_WIDTH, .height = MAX_HEIGHT, .pixel_format = DRM_FORMAT_YVU420,
 		 .handles = { 1, 1, 1 },
 		 .modifier = { AFBC_FORMAT_MOD_SPARSE, AFBC_FORMAT_MOD_SPARSE, 0 },
-		 .pitches = { MAX_WIDTH, DIV_ROUND_UP(MAX_WIDTH, 2), DIV_ROUND_UP(MAX_WIDTH, 2) },
+		 .pitches = { MAX_WIDTH, __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2),
+			      __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) },
 	}
 },
 { .buffer_created = 0,
@@ -259,7 +261,8 @@ static const struct drm_framebuffer_test drm_framebuffer_create_cases[] = {
 	.cmd = { .width = MAX_WIDTH, .height = MAX_HEIGHT, .pixel_format = DRM_FORMAT_YVU420,
 		 .handles = { 1, 1, 1 }, .flags = DRM_MODE_FB_MODIFIERS,
 		 .modifier = { AFBC_FORMAT_MOD_SPARSE, AFBC_FORMAT_MOD_SPARSE, 0 },
-		 .pitches = { MAX_WIDTH, DIV_ROUND_UP(MAX_WIDTH, 2), DIV_ROUND_UP(MAX_WIDTH, 2) },
+		 .pitches = { MAX_WIDTH, __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2),
+			      __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) },
 	}
 },
 { .buffer_created = 1, .name = "YVU420 Valid modifier",
@@ -267,7 +270,8 @@ static const struct drm_framebuffer_test drm_framebuffer_create_cases[] = {
 		 .handles = { 1, 1, 1 }, .flags = DRM_MODE_FB_MODIFIERS,
 		 .modifier = { AFBC_FORMAT_MOD_SPARSE, AFBC_FORMAT_MOD_SPARSE,
 			 AFBC_FORMAT_MOD_SPARSE },
-		 .pitches = { MAX_WIDTH, DIV_ROUND_UP(MAX_WIDTH, 2), DIV_ROUND_UP(MAX_WIDTH, 2) },
+		 .pitches = { MAX_WIDTH, __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2),
+			      __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) },
 	}
 },
 { .buffer_created = 0, .name = "YVU420 Different modifiers per plane",
@@ -275,7 +279,8 @@ static const struct drm_framebuffer_test drm_framebuffer_create_cases[] = {
 		 .handles = { 1, 1, 1 }, .flags = DRM_MODE_FB_MODIFIERS,
 		 .modifier = { AFBC_FORMAT_MOD_SPARSE, AFBC_FORMAT_MOD_SPARSE | AFBC_FORMAT_MOD_YTR,
 			       AFBC_FORMAT_MOD_SPARSE },
-		 .pitches = { MAX_WIDTH, DIV_ROUND_UP(MAX_WIDTH, 2), DIV_ROUND_UP(MAX_WIDTH, 2) },
+		 .pitches = { MAX_WIDTH, __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2),
+			      __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) },
 	}
 },
 { .buffer_created = 0, .name = "YVU420 Modifier for inexistent plane",
@@ -283,7 +288,8 @@ static const struct drm_framebuffer_test drm_framebuffer_create_cases[] = {
 		 .handles = { 1, 1, 1 }, .flags = DRM_MODE_FB_MODIFIERS,
 		 .modifier = { AFBC_FORMAT_MOD_SPARSE, AFBC_FORMAT_MOD_SPARSE,
 			 AFBC_FORMAT_MOD_SPARSE, AFBC_FORMAT_MOD_SPARSE },
-		 .pitches = { MAX_WIDTH, DIV_ROUND_UP(MAX_WIDTH, 2), DIV_ROUND_UP(MAX_WIDTH, 2) },
+		 .pitches = { MAX_WIDTH, __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2),
+			      __KERNEL_DIV_ROUND_UP(MAX_WIDTH, 2) },
 	}
 },
 { .buffer_created = 0, .name = "YUV420_10BIT Invalid modifier(DRM_FORMAT_MOD_LINEAR)",
diff --git a/drivers/input/rmi4/rmi_f30.c b/drivers/input/rmi4/rmi_f30.c
index 35045f161dc2..02a8aaf5fa3a 100644
--- a/drivers/input/rmi4/rmi_f30.c
+++ b/drivers/input/rmi4/rmi_f30.c
@@ -30,7 +30,7 @@
 #define RMI_F30_CTRL_10_NUM_MECH_MOUSE_BTNS	0x03
 
 #define RMI_F30_CTRL_MAX_REGS		32
-#define RMI_F30_CTRL_MAX_BYTES		DIV_ROUND_UP(RMI_F30_CTRL_MAX_REGS, 8)
+#define RMI_F30_CTRL_MAX_BYTES		BITS_TO_BYTES(RMI_F30_CTRL_MAX_REGS)
 #define RMI_F30_CTRL_MAX_REG_BLOCKS	11
 
 #define RMI_F30_CTRL_REGS_MAX_SIZE (RMI_F30_CTRL_MAX_BYTES		\
diff --git a/drivers/input/rmi4/rmi_f3a.c b/drivers/input/rmi4/rmi_f3a.c
index 0e8baed84dbb..34a6c511f95d 100644
--- a/drivers/input/rmi4/rmi_f3a.c
+++ b/drivers/input/rmi4/rmi_f3a.c
@@ -10,7 +10,8 @@
 #include "rmi_driver.h"
 
 #define RMI_F3A_MAX_GPIO_COUNT		128
-#define RMI_F3A_MAX_REG_SIZE		DIV_ROUND_UP(RMI_F3A_MAX_GPIO_COUNT, 8)
+#define RMI_F3A_MAX_REG_SIZE		__KERNEL_DIV_ROUND_UP(		      \
+						     RMI_F3A_MAX_GPIO_COUNT, 8)
 
 /* Defs for Query 0 */
 #define RMI_F3A_GPIO_COUNT		0x7F
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 6503573557fd..b24445c9bc86 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -74,10 +74,10 @@ struct gic_chip_data {
 	void __iomem *raw_cpu_base;
 	u32 percpu_offset;
 #if defined(CONFIG_CPU_PM) || defined(CONFIG_ARM_GIC_PM)
-	u32 saved_spi_enable[DIV_ROUND_UP(1020, 32)];
-	u32 saved_spi_active[DIV_ROUND_UP(1020, 32)];
-	u32 saved_spi_conf[DIV_ROUND_UP(1020, 16)];
-	u32 saved_spi_target[DIV_ROUND_UP(1020, 4)];
+	u32 saved_spi_enable[__KERNEL_DIV_ROUND_UP(1020, 32)];
+	u32 saved_spi_active[__KERNEL_DIV_ROUND_UP(1020, 32)];
+	u32 saved_spi_conf[__KERNEL_DIV_ROUND_UP(1020, 16)];
+	u32 saved_spi_target[__KERNEL_DIV_ROUND_UP(1020, 4)];
 	u32 __percpu *saved_ppi_enable;
 	u32 __percpu *saved_ppi_active;
 	u32 __percpu *saved_ppi_conf;
diff --git a/drivers/irqchip/irq-mst-intc.c b/drivers/irqchip/irq-mst-intc.c
index f6133ae28155..2c03aad7fc15 100644
--- a/drivers/irqchip/irq-mst-intc.c
+++ b/drivers/irqchip/irq-mst-intc.c
@@ -32,7 +32,7 @@ struct mst_intc_chip_data {
 	bool		no_eoi;
 #ifdef CONFIG_PM_SLEEP
 	struct list_head entry;
-	u16 saved_polarity_conf[DIV_ROUND_UP(MST_INTC_MAX_IRQS, 16)];
+	u16 saved_polarity_conf[__KERNEL_DIV_ROUND_UP(MST_INTC_MAX_IRQS, 16)];
 #endif
 };
 
diff --git a/drivers/media/firewire/firedtv-fw.c b/drivers/media/firewire/firedtv-fw.c
index 5f6e97a8d1c0..f952e8ba0878 100644
--- a/drivers/media/firewire/firedtv-fw.c
+++ b/drivers/media/firewire/firedtv-fw.c
@@ -71,7 +71,8 @@ int fdtv_write(struct firedtv *fdtv, u64 addr, void *data, size_t len)
 #define MAX_PACKET_SIZE		1024  /* 776, rounded up to 2^n */
 #define PACKETS_PER_PAGE	(PAGE_SIZE / MAX_PACKET_SIZE)
 #define N_PACKETS		64    /* buffer size */
-#define N_PAGES			DIV_ROUND_UP(N_PACKETS, PACKETS_PER_PAGE)
+#define N_PAGES			__KERNEL_DIV_ROUND_UP(N_PACKETS, \
+						      PACKETS_PER_PAGE)
 #define IRQ_INTERVAL		16
 
 struct fdtv_ir_context {
diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.c b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
index dd73d534ac49..1ba4d9004373 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2.c
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
@@ -350,8 +350,8 @@ static int cio2_hw_init(struct cio2_device *cio2, struct cio2_queue *q)
 	static const int NUM_VCS = 4;
 	static const int SID;	/* Stream id */
 	static const int ENTRY;
-	static const int FBPT_WIDTH = DIV_ROUND_UP(CIO2_MAX_LOPS,
-					CIO2_FBPT_SUBENTRY_UNIT);
+	static const int FBPT_WIDTH = __KERNEL_DIV_ROUND_UP(CIO2_MAX_LOPS,
+						 CIO2_FBPT_SUBENTRY_UNIT);
 	const u32 num_buffers1 = CIO2_MAX_BUFFERS - 1;
 	const struct ipu3_cio2_fmt *fmt;
 	void __iomem *const base = cio2->base;
diff --git a/drivers/media/pci/pt3/pt3.h b/drivers/media/pci/pt3/pt3.h
index a53124438f51..a521eca067b6 100644
--- a/drivers/media/pci/pt3/pt3.h
+++ b/drivers/media/pci/pt3/pt3.h
@@ -66,7 +66,7 @@ struct pt3_i2cbuf {
 
 #define DESCS_IN_PAGE (PAGE_SIZE / sizeof(struct xfer_desc))
 #define MAX_NUM_XFERS (MAX_DATA_BUFS * DATA_BUF_XFERS)
-#define MAX_DESC_BUFS DIV_ROUND_UP(MAX_NUM_XFERS, DESCS_IN_PAGE)
+#define MAX_DESC_BUFS __KERNEL_DIV_ROUND_UP(MAX_NUM_XFERS, DESCS_IN_PAGE)
 
 /* DMA transfer description.
  * device is passed a pointer to this struct, dma-reads it,
diff --git a/drivers/media/platform/nxp/dw100/dw100.c b/drivers/media/platform/nxp/dw100/dw100.c
index 66582e7f92fc..831db5899b5c 100644
--- a/drivers/media/platform/nxp/dw100/dw100.c
+++ b/drivers/media/platform/nxp/dw100/dw100.c
@@ -41,8 +41,8 @@
 
 #define DW100_DEF_W		640u
 #define DW100_DEF_H		480u
-#define DW100_DEF_LUT_W		(DIV_ROUND_UP(DW100_DEF_W, DW100_BLOCK_SIZE) + 1)
-#define DW100_DEF_LUT_H		(DIV_ROUND_UP(DW100_DEF_H, DW100_BLOCK_SIZE) + 1)
+#define DW100_DEF_LUT_W		(__KERNEL_DIV_ROUND_UP(DW100_DEF_W, DW100_BLOCK_SIZE) + 1)
+#define DW100_DEF_LUT_H		(__KERNEL_DIV_ROUND_UP(DW100_DEF_H, DW100_BLOCK_SIZE) + 1)
 
 /*
  * 16 controls have been reserved for this driver for future extension, but
diff --git a/drivers/mfd/twl4030-irq.c b/drivers/mfd/twl4030-irq.c
index 87496c1cb8bc..a32c673e605a 100644
--- a/drivers/mfd/twl4030-irq.c
+++ b/drivers/mfd/twl4030-irq.c
@@ -82,9 +82,9 @@ static int nr_sih_modules;
 	.module		= TWL4030_MODULE_ ## modname, \
 	.control_offset = TWL4030_ ## modname ## _SIH_CTRL, \
 	.bits		= nbits, \
-	.bytes_ixr	= DIV_ROUND_UP(nbits, 8), \
+	.bytes_ixr	= BITS_TO_BYTES(nbits), \
 	.edr_offset	= TWL4030_ ## modname ## _EDR, \
-	.bytes_edr	= DIV_ROUND_UP((2*(nbits)), 8), \
+	.bytes_edr	= BITS_TO_BYTES(2*(nbits)), \
 	.irq_lines	= 2, \
 	.mask = { { \
 		.isr_offset	= TWL4030_ ## modname ## _ISR1, \
diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
index 175bf9b13058..703cdec20780 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
@@ -3155,9 +3155,8 @@ int t4_get_exprom_version(struct adapter *adap, u32 *vers)
 	struct exprom_header {
 		unsigned char hdr_arr[16];	/* must start with 0x55aa */
 		unsigned char hdr_ver[4];	/* Expansion ROM version */
-	} *hdr;
-	u32 exprom_header_buf[DIV_ROUND_UP(sizeof(struct exprom_header),
-					   sizeof(u32))];
+	} __packed *hdr;
+	u32 exprom_header_buf[sizeof(struct exprom_header) / sizeof(u32)];
 	int ret;
 
 	ret = t4_read_flash(adap, FLASH_EXP_ROM_START,
diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/sge.c b/drivers/net/ethernet/chelsio/cxgb4vf/sge.c
index 5b1d746e6563..f01f1fd772c5 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/sge.c
@@ -111,7 +111,8 @@ enum {
 			  sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64),
 	ETHTXQ_MAX_FLITS = ETHTXQ_MAX_SGL_LEN + ETHTXQ_MAX_HDR,
 
-	ETHTXQ_STOP_THRES = 1 + DIV_ROUND_UP(ETHTXQ_MAX_FLITS, TXD_PER_EQ_UNIT),
+	ETHTXQ_STOP_THRES = 1 + __KERNEL_DIV_ROUND_UP(ETHTXQ_MAX_FLITS,
+						      TXD_PER_EQ_UNIT),
 
 	/*
 	 * Max TX descriptor space we allow for an Ethernet packet to be
diff --git a/drivers/net/ethernet/cisco/enic/vnic_rq.h b/drivers/net/ethernet/cisco/enic/vnic_rq.h
index 0bc595abc03b..3882b00d397e 100644
--- a/drivers/net/ethernet/cisco/enic/vnic_rq.h
+++ b/drivers/net/ethernet/cisco/enic/vnic_rq.h
@@ -49,7 +49,7 @@ struct vnic_rq_ctrl {
 #define VNIC_RQ_BUF_BLK_SZ(entries) \
 	(VNIC_RQ_BUF_BLK_ENTRIES(entries) * sizeof(struct vnic_rq_buf))
 #define VNIC_RQ_BUF_BLKS_NEEDED(entries) \
-	DIV_ROUND_UP(entries, VNIC_RQ_BUF_BLK_ENTRIES(entries))
+	__KERNEL_DIV_ROUND_UP(entries, VNIC_RQ_BUF_BLK_ENTRIES(entries))
 #define VNIC_RQ_BUF_BLKS_MAX VNIC_RQ_BUF_BLKS_NEEDED(4096)
 
 struct vnic_rq_buf {
diff --git a/drivers/net/ethernet/cisco/enic/vnic_wq.h b/drivers/net/ethernet/cisco/enic/vnic_wq.h
index 75c526911074..daf62fb30455 100644
--- a/drivers/net/ethernet/cisco/enic/vnic_wq.h
+++ b/drivers/net/ethernet/cisco/enic/vnic_wq.h
@@ -61,7 +61,7 @@ struct vnic_wq_buf {
 #define VNIC_WQ_BUF_BLK_SZ(entries) \
 	(VNIC_WQ_BUF_BLK_ENTRIES(entries) * sizeof(struct vnic_wq_buf))
 #define VNIC_WQ_BUF_BLKS_NEEDED(entries) \
-	DIV_ROUND_UP(entries, VNIC_WQ_BUF_BLK_ENTRIES(entries))
+	__KERNEL_DIV_ROUND_UP(entries, VNIC_WQ_BUF_BLK_ENTRIES(entries))
 #define VNIC_WQ_BUF_BLKS_MAX VNIC_WQ_BUF_BLKS_NEEDED(4096)
 
 struct vnic_wq {
diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h
index 8167cc5fb0df..a5caf9e35bdf 100644
--- a/drivers/net/ethernet/google/gve/gve.h
+++ b/drivers/net/ethernet/google/gve/gve.h
@@ -84,7 +84,8 @@
 /* 2K buffers for DQO-QPL */
 #define GVE_TX_BUF_SIZE_DQO BIT(GVE_TX_BUF_SHIFT_DQO)
 #define GVE_TX_BUFS_PER_PAGE_DQO (PAGE_SIZE >> GVE_TX_BUF_SHIFT_DQO)
-#define GVE_MAX_TX_BUFS_PER_PKT (DIV_ROUND_UP(GVE_DQO_TX_MAX, GVE_TX_BUF_SIZE_DQO))
+#define GVE_MAX_TX_BUFS_PER_PKT (__KERNEL_DIV_ROUND_UP(GVE_DQO_TX_MAX, \
+						       GVE_TX_BUF_SIZE_DQO))
 
 /* If number of free/recyclable buffers are less than this threshold; driver
  * allocs and uses a non-qpl page on the receive path of DQO QPL to free
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h
index b9fc719880bb..4be5d7f11e97 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h
@@ -637,7 +637,7 @@ struct key_info {
 };
 
 #define MAX_KEY_LENGTH	400
-#define MAX_KEY_DWORDS	DIV_ROUND_UP(MAX_KEY_LENGTH / 8, 4)
+#define MAX_KEY_DWORDS	__KERNEL_DIV_ROUND_UP(MAX_KEY_LENGTH / 8, 4)
 #define MAX_KEY_BYTES	(MAX_KEY_DWORDS * 4)
 #define MAX_META_DATA_LENGTH	32
 
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_csr.h b/drivers/net/ethernet/meta/fbnic/fbnic_csr.h
index 02bb81b3c506..85f39bfa3557 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_csr.h
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_csr.h
@@ -628,9 +628,9 @@ enum {
 #define FBNIC_RPC_RSS_KEY(n)		(0x0840c + (n))	/* 0x21030 + 4*n */
 #define FBNIC_RPC_RSS_KEY_BIT_LEN		425
 #define FBNIC_RPC_RSS_KEY_BYTE_LEN \
-	DIV_ROUND_UP(FBNIC_RPC_RSS_KEY_BIT_LEN, 8)
+	BITS_TO_BYTES(FBNIC_RPC_RSS_KEY_BIT_LEN)
 #define FBNIC_RPC_RSS_KEY_DWORD_LEN \
-	DIV_ROUND_UP(FBNIC_RPC_RSS_KEY_BIT_LEN, 32)
+	BITS_TO_U32(FBNIC_RPC_RSS_KEY_BIT_LEN)
 #define FBNIC_RPC_RSS_KEY_LAST_IDX \
 	(FBNIC_RPC_RSS_KEY_DWORD_LEN - 1)
 #define FBNIC_RPC_RSS_KEY_LAST_MASK \
diff --git a/drivers/net/ethernet/qlogic/qed/qed_debug.c b/drivers/net/ethernet/qlogic/qed/qed_debug.c
index 464a72afb758..4de0c94e82c8 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_debug.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_debug.c
@@ -388,7 +388,7 @@ struct split_type_defs {
 
 #define BYTES_IN_DWORD			sizeof(u32)
 /* In the macros below, size and offset are specified in bits */
-#define CEIL_DWORDS(size)		DIV_ROUND_UP(size, 32)
+#define CEIL_DWORDS(size)		BITS_TO_U32(size)
 #define FIELD_BIT_OFFSET(type, field)	type ## _ ## field ## _ ## OFFSET
 #define FIELD_BIT_SIZE(type, field)	type ## _ ## field ## _ ## SIZE
 #define FIELD_DWORD_OFFSET(type, field) \
diff --git a/drivers/net/ethernet/sfc/falcon/falcon.c b/drivers/net/ethernet/sfc/falcon/falcon.c
index 4af56333ea49..2bb785e95f7e 100644
--- a/drivers/net/ethernet/sfc/falcon/falcon.c
+++ b/drivers/net/ethernet/sfc/falcon/falcon.c
@@ -368,7 +368,7 @@ static const struct i2c_algo_bit_data falcon_i2c_bit_operations = {
 	.getscl		= falcon_getscl,
 	.udelay		= 5,
 	/* Wait up to 50 ms for target to let us pull SCL high */
-	.timeout	= DIV_ROUND_UP(HZ, 20),
+	.timeout	= __KERNEL_DIV_ROUND_UP(HZ, 20),
 };
 
 static void falcon_push_irq_moderation(struct ef4_channel *channel)
diff --git a/drivers/net/ethernet/sfc/mcdi.h b/drivers/net/ethernet/sfc/mcdi.h
index cdb17d7c147f..748b7f095090 100644
--- a/drivers/net/ethernet/sfc/mcdi.h
+++ b/drivers/net/ethernet/sfc/mcdi.h
@@ -182,9 +182,9 @@ void efx_mcdi_sensor_event(struct efx_nic *efx, efx_qword_t *ev);
  * 32-bit-aligned.  Also, on Siena we must copy to the MC shared
  * memory strictly 32 bits at a time, so add any necessary padding.
  */
-#define MCDI_TX_BUF_LEN(_len) DIV_ROUND_UP((_len), 4)
+#define MCDI_TX_BUF_LEN(_len) __KERNEL_DIV_ROUND_UP((_len), 4)
 #define _MCDI_DECLARE_BUF(_name, _len)					\
-	efx_dword_t _name[DIV_ROUND_UP(_len, 4)]
+	efx_dword_t _name[__KERNEL_DIV_ROUND_UP(_len, 4)]
 #define MCDI_DECLARE_BUF(_name, _len)					\
 	_MCDI_DECLARE_BUF(_name, _len) = {{{0}}}
 #define MCDI_DECLARE_BUF_ERR(_name)					\
diff --git a/drivers/net/ethernet/sfc/siena/mcdi.h b/drivers/net/ethernet/sfc/siena/mcdi.h
index 06f38e5e6832..55ca192ff6ef 100644
--- a/drivers/net/ethernet/sfc/siena/mcdi.h
+++ b/drivers/net/ethernet/sfc/siena/mcdi.h
@@ -192,9 +192,9 @@ void efx_siena_mcdi_sensor_event(struct efx_nic *efx, efx_qword_t *ev);
  * 32-bit-aligned.  Also, on Siena we must copy to the MC shared
  * memory strictly 32 bits at a time, so add any necessary padding.
  */
-#define MCDI_TX_BUF_LEN(_len) DIV_ROUND_UP((_len), 4)
+#define MCDI_TX_BUF_LEN(_len) __KERNEL_DIV_ROUND_UP((_len), 4)
 #define _MCDI_DECLARE_BUF(_name, _len)					\
-	efx_dword_t _name[DIV_ROUND_UP(_len, 4)]
+	efx_dword_t _name[__KERNEL_DIV_ROUND_UP(_len, 4)]
 #define MCDI_DECLARE_BUF(_name, _len)					\
 	_MCDI_DECLARE_BUF(_name, _len) = {{{0}}}
 #define MCDI_DECLARE_BUF_ERR(_name)					\
diff --git a/drivers/net/ethernet/sfc/siena/ptp.c b/drivers/net/ethernet/sfc/siena/ptp.c
index 062c77c92077..395bc99b865e 100644
--- a/drivers/net/ethernet/sfc/siena/ptp.c
+++ b/drivers/net/ethernet/sfc/siena/ptp.c
@@ -166,7 +166,7 @@ enum ptp_packet_state {
  *         whether that is of no interest.
  */
 struct efx_ptp_match {
-	u32 words[DIV_ROUND_UP(PTP_V1_UUID_LENGTH, 4)];
+	u32 words[__KERNEL_DIV_ROUND_UP(PTP_V1_UUID_LENGTH, 4)];
 	unsigned long expiry;
 	enum ptp_packet_state state;
 };
diff --git a/drivers/net/ethernet/ti/cpsw_ale.h b/drivers/net/ethernet/ti/cpsw_ale.h
index 87b7d1b3a34a..330156ac5314 100644
--- a/drivers/net/ethernet/ti/cpsw_ale.h
+++ b/drivers/net/ethernet/ti/cpsw_ale.h
@@ -154,7 +154,7 @@ enum cpsw_ale_port_state {
 #define ALE_MCAST_FWD_2			3
 
 #define ALE_ENTRY_BITS		68
-#define ALE_ENTRY_WORDS	DIV_ROUND_UP(ALE_ENTRY_BITS, 32)
+#define ALE_ENTRY_WORDS		BITS_TO_U32(ALE_ENTRY_BITS)
 
 struct cpsw_ale *cpsw_ale_create(struct cpsw_ale_params *params);
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index 132148f7b107..477af5db2451 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -729,7 +729,7 @@ struct mt76_testmode_ops {
 struct mt76_testmode_data {
 	enum mt76_testmode_state state;
 
-	u32 param_set[DIV_ROUND_UP(NUM_MT76_TM_ATTRS, 32)];
+	u32 param_set[__KERNEL_DIV_ROUND_UP(NUM_MT76_TM_ATTRS, 32)];
 	struct sk_buff *tx_skb;
 
 	u32 tx_count;
@@ -914,7 +914,7 @@ struct mt76_dev {
 	/* spinclock used to protect wcid pktid linked list */
 	spinlock_t status_lock;
 
-	u32 wcid_mask[DIV_ROUND_UP(MT76_N_WCIDS, 32)];
+	u32 wcid_mask[__KERNEL_DIV_ROUND_UP(MT76_N_WCIDS, 32)];
 
 	u64 vif_mask;
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x0/eeprom.c b/drivers/net/wireless/mediatek/mt76/mt76x0/eeprom.c
index 4de45a56812d..3e2c35ef7acc 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x0/eeprom.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x0/eeprom.c
@@ -15,7 +15,7 @@
 #include "eeprom.h"
 #include "../mt76x02_phy.h"
 
-#define MT_MAP_READS	DIV_ROUND_UP(MT_EFUSE_USAGE_MAP_SIZE, 16)
+#define MT_MAP_READS	__KERNEL_DIV_ROUND_UP(MT_EFUSE_USAGE_MAP_SIZE, 16)
 static int
 mt76x0_efuse_physical_size_check(struct mt76x02_dev *dev)
 {
diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index ef959e66db7c..906d808824b9 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -593,7 +593,7 @@ static void arm_cmn_debugfs_init(struct arm_cmn *cmn, int id) {}
 
 struct arm_cmn_hw_event {
 	struct arm_cmn_node *dn;
-	u64 dtm_idx[DIV_ROUND_UP(CMN_MAX_NODES_PER_EVENT * 2, 64)];
+	u64 dtm_idx[__KERNEL_DIV_ROUND_UP(CMN_MAX_NODES_PER_EVENT * 2, 64)];
 	s8 dtc_idx[CMN_MAX_DTCS];
 	u8 num_dns;
 	u8 dtm_offset;
diff --git a/drivers/scsi/fnic/vnic_rq.h b/drivers/scsi/fnic/vnic_rq.h
index 1066255de808..e0bc651f78c0 100644
--- a/drivers/scsi/fnic/vnic_rq.h
+++ b/drivers/scsi/fnic/vnic_rq.h
@@ -64,7 +64,7 @@ struct vnic_rq_ctrl {
 #define VNIC_RQ_BUF_BLK_SZ \
 	(VNIC_RQ_BUF_BLK_ENTRIES * sizeof(struct vnic_rq_buf))
 #define VNIC_RQ_BUF_BLKS_NEEDED(entries) \
-	DIV_ROUND_UP(entries, VNIC_RQ_BUF_BLK_ENTRIES)
+	__KERNEL_DIV_ROUND_UP(entries, VNIC_RQ_BUF_BLK_ENTRIES)
 #define VNIC_RQ_BUF_BLKS_MAX VNIC_RQ_BUF_BLKS_NEEDED(4096)
 
 struct vnic_rq_buf {
diff --git a/drivers/scsi/fnic/vnic_wq.h b/drivers/scsi/fnic/vnic_wq.h
index 041618e13ce2..ab0b04f6c2a7 100644
--- a/drivers/scsi/fnic/vnic_wq.h
+++ b/drivers/scsi/fnic/vnic_wq.h
@@ -69,7 +69,7 @@ struct vnic_wq_buf {
 #define VNIC_WQ_BUF_BLK_SZ \
 	(VNIC_WQ_BUF_BLK_ENTRIES * sizeof(struct vnic_wq_buf))
 #define VNIC_WQ_BUF_BLKS_NEEDED(entries) \
-	DIV_ROUND_UP(entries, VNIC_WQ_BUF_BLK_ENTRIES)
+	__KERNEL_DIV_ROUND_UP(entries, VNIC_WQ_BUF_BLK_ENTRIES)
 #define VNIC_WQ_BUF_BLKS_MAX VNIC_WQ_BUF_BLKS_NEEDED(4096)
 
 struct vnic_wq {
diff --git a/drivers/scsi/snic/vnic_wq.h b/drivers/scsi/snic/vnic_wq.h
index 1415da4b68dc..6cfe512eb2d0 100644
--- a/drivers/scsi/snic/vnic_wq.h
+++ b/drivers/scsi/snic/vnic_wq.h
@@ -52,9 +52,7 @@ struct vnic_wq_buf {
 #define VNIC_WQ_BUF_BLK_SZ \
 	(VNIC_WQ_BUF_DFLT_BLK_ENTRIES * sizeof(struct vnic_wq_buf))
 #define VNIC_WQ_BUF_BLKS_NEEDED(entries) \
-	DIV_ROUND_UP(entries, VNIC_WQ_BUF_DFLT_BLK_ENTRIES)
-#define VNIC_WQ_BUF_BLKS_NEEDED(entries) \
-	DIV_ROUND_UP(entries, VNIC_WQ_BUF_DFLT_BLK_ENTRIES)
+	__KERNEL_DIV_ROUND_UP(entries, VNIC_WQ_BUF_DFLT_BLK_ENTRIES)
 #define VNIC_WQ_BUF_BLKS_MAX VNIC_WQ_BUF_BLKS_NEEDED(4096)
 
 struct vnic_wq {
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 51b3124b0d56..184d46b822d8 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -49,7 +49,8 @@
 
 #include "xenbus.h"
 
-#define XENBUS_PAGES(_grants)	(DIV_ROUND_UP(_grants, XEN_PFN_PER_PAGE))
+#define XENBUS_PAGES(_grants)	(__KERNEL_DIV_ROUND_UP(_grants, \
+						       XEN_PFN_PER_PAGE))
 
 #define XENBUS_MAX_RING_PAGES	(XENBUS_PAGES(XENBUS_MAX_RING_GRANTS))
 
diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
index d0768239a1c9..8df9c4d91993 100644
--- a/fs/ceph/crypto.h
+++ b/fs/ceph/crypto.h
@@ -89,7 +89,7 @@ static inline u32 ceph_fscrypt_auth_len(struct ceph_fscrypt_auth *fa)
  */
 #define CEPH_NOHASH_NAME_MAX (180 - SHA256_DIGEST_SIZE)
 
-#define CEPH_BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3)
+#define CEPH_BASE64_CHARS(nbytes) __KERNEL_DIV_ROUND_UP((nbytes) * 4, 3)
 
 int ceph_base64_encode(const u8 *src, int srclen, char *dst);
 int ceph_base64_decode(const char *src, int srclen, u8 *dst);
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 54b3421501e9..091386905d06 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -5010,7 +5010,8 @@ static void check_new_map(struct ceph_mds_client *mdsc,
 	int i, j, err;
 	int oldstate, newstate;
 	struct ceph_mds_session *s;
-	unsigned long targets[DIV_ROUND_UP(CEPH_MAX_MDS, sizeof(unsigned long))] = {0};
+	unsigned long targets[__KERNEL_DIV_ROUND_UP(CEPH_MAX_MDS,
+						    sizeof(unsigned long))] = {0};
 	struct ceph_client *cl = mdsc->fsc->client;
 
 	doutc(cl, "new %u old %u\n", newmap->m_epoch, oldmap->m_epoch);
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 2b123b070a42..4cd1390ef25e 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -7,7 +7,8 @@
 #include "compress.h"
 #include <linux/lz4.h>
 
-#define LZ4_MAX_DISTANCE_PAGES	(DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1)
+#define LZ4_MAX_DISTANCE_PAGES \
+	(__KERNEL_DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1)
 
 struct z_erofs_lz4_decompress_ctx {
 	struct z_erofs_decompress_req *rq;
@@ -60,8 +61,7 @@ static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx,
 {
 	struct z_erofs_decompress_req *rq = ctx->rq;
 	struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL };
-	unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES,
-					   BITS_PER_LONG)] = { 0 };
+	unsigned long bounced[BITS_TO_LONGS(LZ4_MAX_DISTANCE_PAGES)] = { 0 };
 	unsigned int lz4_max_distance_pages =
 				EROFS_SB(rq->sb)->lz4.max_distance_pages;
 	void *kaddr = NULL;
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index 78be6964a8a0..f7a882cfb259 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -47,7 +47,7 @@ enum {
 #define ES_IDX_STREAM		1
 #define ES_IDX_FIRST_FILENAME	2
 #define EXFAT_FILENAME_ENTRY_NUM(name_len) \
-	DIV_ROUND_UP(name_len, EXFAT_FILE_NAME_LEN)
+	__KERNEL_DIV_ROUND_UP(name_len, EXFAT_FILE_NAME_LEN)
 #define ES_IDX_LAST_FILENAME(name_len)	\
 	(ES_IDX_FIRST_FILENAME + EXFAT_FILENAME_ENTRY_NUM(name_len) - 1)
 
@@ -147,7 +147,8 @@ enum {
  * The 608 bytes are in 3 sectors at most (even 512 Byte sector).
  */
 #define DIR_CACHE_SIZE		\
-	(DIV_ROUND_UP(EXFAT_DEN_TO_B(ES_MAX_ENTRY_NUM), SECTOR_SIZE) + 1)
+	(__KERNEL_DIV_ROUND_UP(EXFAT_DEN_TO_B(ES_MAX_ENTRY_NUM), SECTOR_SIZE) \
+	 + 1)
 
 /* Superblock flags */
 #define EXFAT_FLAGS_SHUTDOWN	1
diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
index 1924c4a2077b..25e2f52e4485 100644
--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -1161,7 +1161,7 @@ int nfs42_proc_clone(struct file *src_f, struct file *dst_f,
 	return err;
 }
 
-#define NFS4XATTR_MAXPAGES DIV_ROUND_UP(XATTR_SIZE_MAX, PAGE_SIZE)
+#define NFS4XATTR_MAXPAGES __KERNEL_DIV_ROUND_UP(XATTR_SIZE_MAX, PAGE_SIZE)
 
 static int _nfs42_proc_removexattr(struct inode *inode, const char *name)
 {
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index df9669d4ded7..d2c7122ecd68 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5954,7 +5954,7 @@ static bool nfs4_server_supports_acls(const struct nfs_server *server,
  * it's OK to put sizeof(void) * (XATTR_SIZE_MAX/PAGE_SIZE) bytes on
  * the stack.
  */
-#define NFS4ACL_MAXPAGES DIV_ROUND_UP(XATTR_SIZE_MAX, PAGE_SIZE)
+#define NFS4ACL_MAXPAGES __KERNEL_DIV_ROUND_UP(XATTR_SIZE_MAX, PAGE_SIZE)
 
 int nfs4_buf_to_pages_noslab(const void *buf, size_t buflen,
 		struct page **pages)
diff --git a/fs/nfs/nfs4session.h b/fs/nfs/nfs4session.h
index 351616c61df5..5af450df4a3f 100644
--- a/fs/nfs/nfs4session.h
+++ b/fs/nfs/nfs4session.h
@@ -35,7 +35,7 @@ enum nfs4_slot_tbl_state {
 	NFS4_SLOT_TBL_DRAINING,
 };
 
-#define SLOT_TABLE_SZ DIV_ROUND_UP(NFS4_MAX_SLOT_TABLE, BITS_PER_LONG)
+#define SLOT_TABLE_SZ BITS_TO_LONGS(NFS4_MAX_SLOT_TABLE)
 struct nfs4_slot_table {
 	struct nfs4_session *session;		/* Parent session */
 	struct nfs4_slot *slots;		/* seqid per slot */
diff --git a/fs/orangefs/orangefs-bufmap.c b/fs/orangefs/orangefs-bufmap.c
index edcca4beb765..1bad9687ebcb 100644
--- a/fs/orangefs/orangefs-bufmap.c
+++ b/fs/orangefs/orangefs-bufmap.c
@@ -158,7 +158,7 @@ static struct orangefs_bufmap {
 	unsigned long *buffer_index_array;
 
 	/* array to track usage of buffer descriptors for readdir */
-#define N DIV_ROUND_UP(ORANGEFS_READDIR_DEFAULT_DESC_COUNT, BITS_PER_LONG)
+#define N BITS_TO_LONGS(ORANGEFS_READDIR_DEFAULT_DESC_COUNT)
 	unsigned long readdir_index_array[N];
 #undef N
 } *__orangefs_bufmap;
diff --git a/include/crypto/internal/ecc.h b/include/crypto/internal/ecc.h
index 57cd75242141..24711384ddd1 100644
--- a/include/crypto/internal/ecc.h
+++ b/include/crypto/internal/ecc.h
@@ -34,7 +34,7 @@
 #define ECC_CURVE_NIST_P256_DIGITS  4
 #define ECC_CURVE_NIST_P384_DIGITS  6
 #define ECC_CURVE_NIST_P521_DIGITS  9
-#define ECC_MAX_DIGITS              DIV_ROUND_UP(521, 64) /* NIST P521 */
+#define ECC_MAX_DIGITS __KERNEL_DIV_ROUND_UP(521, 64) /* NIST P521 */
 
 #define ECC_DIGITS_TO_BYTES_SHIFT 3
 
diff --git a/include/linux/can/length.h b/include/linux/can/length.h
index abc978b38f79..20f90c8e6eaf 100644
--- a/include/linux/can/length.h
+++ b/include/linux/can/length.h
@@ -238,9 +238,8 @@
  * (rounded up, including intermission)
  */
 #define can_frame_bytes(is_fd, is_eff, bitstuffing, data_len)	\
-	DIV_ROUND_UP(can_frame_bits(is_fd, is_eff, bitstuffing,	\
-				    true, data_len),		\
-		     BITS_PER_BYTE)
+	BITS_TO_BYTES(can_frame_bits(is_fd, is_eff, bitstuffing,\
+				     true, data_len))
 
 /*
  * Maximum size of a Classical CAN frame
diff --git a/include/linux/gpio/gpio-nomadik.h b/include/linux/gpio/gpio-nomadik.h
index b5a84864650d..067ce7a068c3 100644
--- a/include/linux/gpio/gpio-nomadik.h
+++ b/include/linux/gpio/gpio-nomadik.h
@@ -10,7 +10,7 @@ struct fwnode_handle;
 
 #define GPIO_BLOCK_SHIFT 5
 #define NMK_GPIO_PER_CHIP BIT(GPIO_BLOCK_SHIFT)
-#define NMK_MAX_BANKS DIV_ROUND_UP(512, NMK_GPIO_PER_CHIP)
+#define NMK_MAX_BANKS __KERNEL_DIV_ROUND_UP(512, NMK_GPIO_PER_CHIP)
 
 /* Register in the logic block */
 #define NMK_GPIO_DAT	0x00
diff --git a/include/linux/math.h b/include/linux/math.h
index 0198c92cbe3e..6f541d765d8a 100644
--- a/include/linux/math.h
+++ b/include/linux/math.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_MATH_H
 #define _LINUX_MATH_H
 
+#include <linux/log2.h>
 #include <linux/types.h>
 #include <asm/div64.h>
 #include <uapi/linux/kernel.h>
@@ -46,7 +47,10 @@
 #define DIV_ROUND_UP_POW2(n, d) \
 	((n) / (d) + !!((n) & ((d) - 1)))
 
-#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
+#define DIV_ROUND_UP(n, d)						\
+	(__builtin_constant_p(d) && is_power_of_2(d)			\
+		? DIV_ROUND_UP_POW2(n, d)				\
+		: __KERNEL_DIV_ROUND_UP(n, d))
 
 #define DIV_ROUND_DOWN_ULL(ll, d) \
 	({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; })
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 9540b41894da..652edb86f379 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1880,7 +1880,8 @@ struct mem_section {
 #endif
 
 #define SECTION_NR_TO_ROOT(sec)	((sec) / SECTIONS_PER_ROOT)
-#define NR_SECTION_ROOTS	DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
+#define NR_SECTION_ROOTS	__KERNEL_DIV_ROUND_UP(NR_MEM_SECTIONS, \
+						      SECTIONS_PER_ROOT)
 #define SECTION_ROOT_MASK	(SECTIONS_PER_ROOT - 1)
 
 #ifdef CONFIG_SPARSEMEM_EXTREME
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 71fbebfa43c7..8141f70e29b1 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -820,8 +820,7 @@ enum pnfs_update_layout_reason {
 	PNFS_UPDATE_LAYOUT_EXIT,
 };
 
-#define NFS4_OP_MAP_NUM_LONGS					\
-	DIV_ROUND_UP(LAST_NFS4_OP, 8 * sizeof(unsigned long))
+#define NFS4_OP_MAP_NUM_LONGS BITS_TO_LONGS(LAST_NFS4_OP)
 #define NFS4_OP_MAP_NUM_WORDS \
 	(NFS4_OP_MAP_NUM_LONGS * sizeof(unsigned long) / sizeof(u32))
 struct nfs4_op_map {
diff --git a/include/linux/rcu_node_tree.h b/include/linux/rcu_node_tree.h
index 78feb8ba7358..3fb40bbb0455 100644
--- a/include/linux/rcu_node_tree.h
+++ b/include/linux/rcu_node_tree.h
@@ -61,7 +61,7 @@
 #elif NR_CPUS <= RCU_FANOUT_2
 #  define RCU_NUM_LVLS	      2
 #  define NUM_RCU_LVL_0	      1
-#  define NUM_RCU_LVL_1	      DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
+#  define NUM_RCU_LVL_1	      __KERNEL_DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
 #  define NUM_RCU_NODES	      (NUM_RCU_LVL_0 + NUM_RCU_LVL_1)
 #  define NUM_RCU_LVL_INIT    { NUM_RCU_LVL_0, NUM_RCU_LVL_1 }
 #  define RCU_NODE_NAME_INIT  { "rcu_node_0", "rcu_node_1" }
@@ -69,8 +69,8 @@
 #elif NR_CPUS <= RCU_FANOUT_3
 #  define RCU_NUM_LVLS	      3
 #  define NUM_RCU_LVL_0	      1
-#  define NUM_RCU_LVL_1	      DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
-#  define NUM_RCU_LVL_2	      DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
+#  define NUM_RCU_LVL_1	      __KERNEL_DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
+#  define NUM_RCU_LVL_2	      __KERNEL_DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
 #  define NUM_RCU_NODES	      (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2)
 #  define NUM_RCU_LVL_INIT    { NUM_RCU_LVL_0, NUM_RCU_LVL_1, NUM_RCU_LVL_2 }
 #  define RCU_NODE_NAME_INIT  { "rcu_node_0", "rcu_node_1", "rcu_node_2" }
@@ -78,9 +78,9 @@
 #elif NR_CPUS <= RCU_FANOUT_4
 #  define RCU_NUM_LVLS	      4
 #  define NUM_RCU_LVL_0	      1
-#  define NUM_RCU_LVL_1	      DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3)
-#  define NUM_RCU_LVL_2	      DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
-#  define NUM_RCU_LVL_3	      DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
+#  define NUM_RCU_LVL_1	      __KERNEL_DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3)
+#  define NUM_RCU_LVL_2	      __KERNEL_DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
+#  define NUM_RCU_LVL_3	      __KERNEL_DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
 #  define NUM_RCU_NODES	      (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3)
 #  define NUM_RCU_LVL_INIT    { NUM_RCU_LVL_0, NUM_RCU_LVL_1, NUM_RCU_LVL_2, NUM_RCU_LVL_3 }
 #  define RCU_NODE_NAME_INIT  { "rcu_node_0", "rcu_node_1", "rcu_node_2", "rcu_node_3" }
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index f88daaa76d83..59989f26ed6b 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -88,7 +88,7 @@ static inline unsigned int tcp_optlen(const struct sk_buff *skb)
 
 /* TCP Fast Open Cookie as stored in memory */
 struct tcp_fastopen_cookie {
-	__le64	val[DIV_ROUND_UP(TCP_FASTOPEN_COOKIE_MAX, sizeof(u64))];
+	__le64	val[__KERNEL_DIV_ROUND_UP(TCP_FASTOPEN_COOKIE_MAX, sizeof(u64))];
 	s8	len;
 	bool	exp;	/* In RFC6994 experimental option format */
 };
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 363d7dd2255a..e9f6d37ca2d5 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -5723,7 +5723,7 @@ struct wiphy {
 	u16 max_acl_mac_addrs;
 
 	u32 flags, regulatory_flags, features;
-	u8 ext_features[DIV_ROUND_UP(NUM_NL80211_EXT_FEATURES, 8)];
+	u8 ext_features[__KERNEL_DIV_ROUND_UP(NUM_NL80211_EXT_FEATURES, 8)];
 
 	u32 ap_sme_capa;
 
diff --git a/kernel/events/core.c b/kernel/events/core.c
index bcb09e011e9e..a75280e57903 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -464,7 +464,7 @@ int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free'
 
 int sysctl_perf_event_sample_rate __read_mostly	= DEFAULT_MAX_SAMPLE_RATE;
 
-static int max_samples_per_tick __read_mostly	= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
+static int max_samples_per_tick __read_mostly	= __KERNEL_DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
 static int perf_sample_period_ns __read_mostly	= DEFAULT_SAMPLE_PERIOD_NS;
 
 static int perf_sample_allowed_ns __read_mostly =
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 82b884b67152..d5cc164088e5 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -529,8 +529,8 @@ static int swap_writer_finish(struct swap_map_handle *handle,
 #define UNC_SIZE	(UNC_PAGES * PAGE_SIZE)
 
 /* Number of pages we need for compressed data (worst case). */
-#define CMP_PAGES	DIV_ROUND_UP(bytes_worst_compress(UNC_SIZE) + \
-				CMP_HEADER, PAGE_SIZE)
+#define CMP_PAGES	__KERNEL_DIV_ROUND_UP(bytes_worst_compress(UNC_SIZE) + \
+					      CMP_HEADER, PAGE_SIZE)
 #define CMP_SIZE	(CMP_PAGES * PAGE_SIZE)
 
 /* Maximum number of threads for compression/decompression. */
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 59314da5eb60..b99a0c64c543 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -144,7 +144,7 @@ static struct rcu_tasks rt_name =							\
 	.call_func = call,								\
 	.wait_state = TASK_UNINTERRUPTIBLE,						\
 	.rtpcpu = &rt_name ## __percpu,							\
-	.lazy_jiffies = DIV_ROUND_UP(HZ, 4),						\
+	.lazy_jiffies = __KERNEL_DIV_ROUND_UP(HZ, 4),					\
 	.name = n,									\
 	.percpu_enqueue_shift = order_base_2(CONFIG_NR_CPUS),				\
 	.percpu_enqueue_lim = 1,							\
diff --git a/lib/bch.c b/lib/bch.c
index 1c0cb07cdfeb..4777d5fe0185 100644
--- a/lib/bch.c
+++ b/lib/bch.c
@@ -92,7 +92,7 @@
 #define BCH_ECC_WORDS(_p)      DIV_ROUND_UP(GF_M(_p)*GF_T(_p), 32)
 #define BCH_ECC_BYTES(_p)      DIV_ROUND_UP(GF_M(_p)*GF_T(_p), 8)
 
-#define BCH_ECC_MAX_WORDS      DIV_ROUND_UP(BCH_MAX_M * BCH_MAX_T, 32)
+#define BCH_ECC_MAX_WORDS      __KERNEL_DIV_ROUND_UP(BCH_MAX_M * BCH_MAX_T, 32)
 
 #ifndef dbg
 #define dbg(_fmt, args...)     do {} while (0)
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 65a75d58ed9e..df34bb85fd88 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -693,8 +693,8 @@ static void __init test_bitmap_arr32(void)
 		}
 
 		if (nbits < EXP1_IN_BITS - 32)
-			expect_eq_uint(arr[DIV_ROUND_UP(nbits, 32)],
-								0xa5a5a5a5);
+			expect_eq_uint(arr[__KERNEL_DIV_ROUND_UP(nbits, 32)],
+				       0xa5a5a5a5);
 	}
 }
 
@@ -728,7 +728,8 @@ static void __init test_bitmap_arr64(void)
 		}
 
 		if (nbits < EXP1_IN_BITS - 64)
-			expect_eq_uint(arr[DIV_ROUND_UP(nbits, 64)], 0xa5a5a5a5);
+			expect_eq_uint(arr[__KERNEL_DIV_ROUND_UP(nbits, 64)],
+				       0xa5a5a5a5);
 	}
 }
 
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 6d0e47f7ae33..5b4ec6900999 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -128,8 +128,9 @@
  *  (reason above)
  */
 #define ZS_SIZE_CLASS_DELTA	(PAGE_SIZE >> CLASS_BITS)
-#define ZS_SIZE_CLASSES	(DIV_ROUND_UP(ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE, \
-				      ZS_SIZE_CLASS_DELTA) + 1)
+#define ZS_SIZE_CLASSES	(__KERNEL_DIV_ROUND_UP(ZS_MAX_ALLOC_SIZE -	\
+					       ZS_MIN_ALLOC_SIZE,	\
+					       ZS_SIZE_CLASS_DELTA) + 1)
 
 /*
  * Pages are distinguished by the ratio of used memory (that is the ratio
diff --git a/net/ethtool/bitset.c b/net/ethtool/bitset.c
index f0883357d12e..abce56a56801 100644
--- a/net/ethtool/bitset.c
+++ b/net/ethtool/bitset.c
@@ -734,7 +734,7 @@ int ethnl_parse_bitset(unsigned long *val, unsigned long *mask,
  * majority of bitmaps used by ethtool.
  */
 #define ETHNL_SMALL_BITMAP_BITS 128
-#define ETHNL_SMALL_BITMAP_WORDS DIV_ROUND_UP(ETHNL_SMALL_BITMAP_BITS, 32)
+#define ETHNL_SMALL_BITMAP_WORDS BITS_TO_U32(ETHNL_SMALL_BITMAP_BITS)
 
 int ethnl_bitset_size(const unsigned long *val, const unsigned long *mask,
 		      unsigned int nbits, ethnl_string_array_t names,
diff --git a/net/ethtool/common.h b/net/ethtool/common.h
index 850eadde4bfc..9635589e9d1c 100644
--- a/net/ethtool/common.h
+++ b/net/ethtool/common.h
@@ -6,7 +6,7 @@
 #include <linux/netdevice.h>
 #include <linux/ethtool.h>
 
-#define ETHTOOL_DEV_FEATURE_WORDS	DIV_ROUND_UP(NETDEV_FEATURE_COUNT, 32)
+#define ETHTOOL_DEV_FEATURE_WORDS	BITS_TO_U32(NETDEV_FEATURE_COUNT)
 
 /* compose link mode index from speed, type and duplex */
 #define ETHTOOL_LINK_MODE(speed, type, duplex) \
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 34bee42e1247..0406b5706133 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -421,7 +421,7 @@ convert_link_ksettings_to_legacy_settings(
 
 /* number of 32-bit words to store the user's link mode bitmaps */
 #define __ETHTOOL_LINK_MODE_MASK_NU32			\
-	DIV_ROUND_UP(__ETHTOOL_LINK_MODE_MASK_NBITS, 32)
+	BITS_TO_U32(__ETHTOOL_LINK_MODE_MASK_NBITS)
 
 /* layout of the struct passed from/to userland */
 struct ethtool_link_usettings {
diff --git a/net/mac80211/airtime.c b/net/mac80211/airtime.c
index c61df637232a..e17d5d63b055 100644
--- a/net/mac80211/airtime.c
+++ b/net/mac80211/airtime.c
@@ -16,7 +16,7 @@
 /* Number of kilo-symbols (symbols * 1024) for a packet with (bps) bits per
  * symbol. We use k-symbols to avoid rounding in the _TIME macros below.
  */
-#define MCS_N_KSYMS(bps) DIV_ROUND_UP(MCS_NBITS << 10, (bps))
+#define MCS_N_KSYMS(bps) __KERNEL_DIV_ROUND_UP(MCS_NBITS << 10, (bps))
 
 /* Transmission time (in 1024 * usec) for a packet containing (ksyms) * 1024
  * symbols.
diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 706cbc99f718..271ec1c6ad4f 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -23,7 +23,7 @@
 #define MCS_NBITS ((AVG_PKT_SIZE * AVG_AMPDU_SIZE) << 3)
 
 /* Number of symbols for a packet with (bps) bits per symbol */
-#define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
+#define MCS_NSYMS(bps) __KERNEL_DIV_ROUND_UP(MCS_NBITS, (bps))
 
 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
 #define MCS_SYMBOL_TIME(sgi, syms)					\
diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h
index 832c85c70d83..53082a3c1453 100644
--- a/security/selinux/ss/sidtab.h
+++ b/security/selinux/ss/sidtab.h
@@ -50,8 +50,9 @@ union sidtab_entry_inner {
 #define SIDTAB_MAX	U32_MAX
 /* ensure enough tree levels for SIDTAB_MAX entries */
 #define SIDTAB_MAX_LEVEL                                                   \
-	DIV_ROUND_UP(SIDTAB_MAX_BITS - size_to_shift(SIDTAB_LEAF_ENTRIES), \
-		     SIDTAB_INNER_SHIFT)
+	__KERNEL_DIV_ROUND_UP(SIDTAB_MAX_BITS -				   \
+			      size_to_shift(SIDTAB_LEAF_ENTRIES),	   \
+			      SIDTAB_INNER_SHIFT)
 
 struct sidtab_node_leaf {
 	struct sidtab_entry entries[SIDTAB_LEAF_ENTRIES];
diff --git a/sound/usb/misc/ua101.c b/sound/usb/misc/ua101.c
index 4f6b20ed29dd..ba3743cff639 100644
--- a/sound/usb/misc/ua101.c
+++ b/sound/usb/misc/ua101.c
@@ -36,7 +36,7 @@ MODULE_LICENSE("GPL v2");
 #define DEFAULT_QUEUE_LENGTH	21
 
 #define MAX_PACKET_SIZE		672 /* hardware specific */
-#define MAX_MEMORY_BUFFERS	DIV_ROUND_UP(MAX_QUEUE_LENGTH, \
+#define MAX_MEMORY_BUFFERS	__KERNEL_DIV_ROUND_UP(MAX_QUEUE_LENGTH, \
 					     PAGE_SIZE / MAX_PACKET_SIZE)
 
 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
-- 
2.43.0

[PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Lukas Wunner]

KEYCTL_PKEY_QUERY system calls for ecdsa keys return the key size as
max_enc_size and max_dec_size, even though such keys cannot be used for
encryption/decryption.  They're exclusively for signature generation or
verification.

Only rsa keys with pkcs1 encoding can also be used for encryption or
decryption.

Return 0 instead for ecdsa keys (as well as ecrdsa keys).

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
---
 crypto/asymmetric_keys/public_key.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index bf165d321440..dd44a966947f 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -188,6 +188,8 @@ static int software_key_query(const struct kernel_pkey_params *params,
 	ptr = pkey_pack_u32(ptr, pkey->paramlen);
 	memcpy(ptr, pkey->params, pkey->paramlen);
 
+	memset(info, 0, sizeof(*info));
+
 	if (issig) {
 		sig = crypto_alloc_sig(alg_name, 0, 0);
 		if (IS_ERR(sig)) {
@@ -211,6 +213,9 @@ static int software_key_query(const struct kernel_pkey_params *params,
 			info->supported_ops |= KEYCTL_SUPPORTS_SIGN;
 
 		if (strcmp(params->encoding, "pkcs1") == 0) {
+			info->max_enc_size = len;
+			info->max_dec_size = len;
+
 			info->supported_ops |= KEYCTL_SUPPORTS_ENCRYPT;
 			if (pkey->key_is_private)
 				info->supported_ops |= KEYCTL_SUPPORTS_DECRYPT;
@@ -232,6 +237,8 @@ static int software_key_query(const struct kernel_pkey_params *params,
 		len = crypto_akcipher_maxsize(tfm);
 		info->max_sig_size = len;
 		info->max_data_size = len;
+		info->max_enc_size = len;
+		info->max_dec_size = len;
 
 		info->supported_ops = KEYCTL_SUPPORTS_ENCRYPT;
 		if (pkey->key_is_private)
@@ -239,8 +246,6 @@ static int software_key_query(const struct kernel_pkey_params *params,
 	}
 
 	info->key_size = len * 8;
-	info->max_enc_size = len;
-	info->max_dec_size = len;
 
 	ret = 0;
 
-- 
2.43.0

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Herbert Xu]

On Sun, Feb 02, 2025 at 08:00:53PM +0100, Lukas Wunner wrote:
> KEYCTL_PKEY_QUERY system calls for ecdsa keys return the key size as
> max_enc_size and max_dec_size, even though such keys cannot be used for
> encryption/decryption.  They're exclusively for signature generation or
> verification.
> 
> Only rsa keys with pkcs1 encoding can also be used for encryption or
> decryption.
> 
> Return 0 instead for ecdsa keys (as well as ecrdsa keys).
> 
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
> ---
>  crypto/asymmetric_keys/public_key.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)

I think we should discuss who is using these user-space APIs
before doing any more work on them.  The in-kernel asymmetric
crypto code is not safe against side-channel attacks.  As there
are no in-kernel users of private-key functionality, we should
consider getting rid of private key support completely.

As it stands the only user is this user-space API.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Lukas Wunner]

On Sun, Feb 09, 2025 at 05:58:07PM +0800, Herbert Xu wrote:
> On Sun, Feb 02, 2025 at 08:00:53PM +0100, Lukas Wunner wrote:
> > KEYCTL_PKEY_QUERY system calls for ecdsa keys return the key size as
> > max_enc_size and max_dec_size, even though such keys cannot be used for
> > encryption/decryption.  They're exclusively for signature generation or
> > verification.
> > 
> > Only rsa keys with pkcs1 encoding can also be used for encryption or
> > decryption.
> > 
> > Return 0 instead for ecdsa keys (as well as ecrdsa keys).
> 
> I think we should discuss who is using these user-space APIs
> before doing any more work on them.  The in-kernel asymmetric
> crypto code is not safe against side-channel attacks.  As there
> are no in-kernel users of private-key functionality, we should
> consider getting rid of private key support completely.
> 
> As it stands the only user is this user-space API.

Personally I am not using this user-space API, so I don't really
have a dog in this fight.  I just noticed the incorrect output
for KEYCTL_PKEY_QUERY and thought it might be better if it's fixed.

One user of this API is the Embedded Linux Library, which in turn
is used by Intel Wireless Daemon:

https://git.kernel.org/pub/scm/libs/ell/ell.git/tree/ell/key.c
https://git.kernel.org/pub/scm/network/wireless/iwd.git/tree/src/eap-tls.c

Basically IWD seems to be invoking the kernel's Key Retention Service for
EAP authentication.  It's still maintained and known to have active users,
so removing the user-space keyctl ABI would definitely cause breakage.

I've just checked for other reverse dependencies of the "libell0" package
on Debian, it lists "bluez" and "mptcpd" but looking at their source code
reveals they're not using the l_key_*() functions, so they would not be
affected by removal.

There's a keyring package for go, so I suppose there may be go applications
out there using it:

https://pkg.go.dev/pault.ag/go/keyring

Then there's the keyutils library...

https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git

...and listing the reverse dependencies for "libkeyutils1" on Debian
reveals a slew of packages which are using it:

  gdm3 samba-libs sssd-common python3-keyutils nfs-common ndctl
  mokutil kstart libkrb5-3 kafs-client ima-evm-utils ceph-common
  libecryptfs1 ecryptfs-utils cifs-utils

And "python3-keyutils" in turn has this reverse dependency:

  udiskie

Finally, folks at cloudflare praised the kernel's Key Retention Service
and encouraged everyone to use it... :)

https://blog.cloudflare.com/the-linux-kernel-key-retention-service-and-why-you-should-use-it-in-your-next-application/

In short, it doesn't seem trivial to drop this user-space API.

Thanks,

Lukas

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Ignat Korchagin]

On Sun, Feb 9, 2025 at 11:29 AM Lukas Wunner <lukas@wunner.de> wrote:
>
> On Sun, Feb 09, 2025 at 05:58:07PM +0800, Herbert Xu wrote:
> > On Sun, Feb 02, 2025 at 08:00:53PM +0100, Lukas Wunner wrote:
> > > KEYCTL_PKEY_QUERY system calls for ecdsa keys return the key size as
> > > max_enc_size and max_dec_size, even though such keys cannot be used for
> > > encryption/decryption.  They're exclusively for signature generation or
> > > verification.
> > >
> > > Only rsa keys with pkcs1 encoding can also be used for encryption or
> > > decryption.
> > >
> > > Return 0 instead for ecdsa keys (as well as ecrdsa keys).
> >
> > I think we should discuss who is using these user-space APIs
> > before doing any more work on them.  The in-kernel asymmetric
> > crypto code is not safe against side-channel attacks.  As there
> > are no in-kernel users of private-key functionality, we should
> > consider getting rid of private key support completely.
> >
> > As it stands the only user is this user-space API.

Please don't! Keyrings + asymmetric crypto is a great building block
for secure architectures. If anything we want more of this, not less.
We can get rid of various ssh-agents and anything that tries to keep
cryptographic material in a separate address space. It is the most
straightforward way to avoid heartbleed-like vulnerabilities [1].
Before this we had to design whole solutions just to separate private
keys from network facing code [2].

Now, in-kernel RSA implementation is indeed a downside, but again -
one could swap internal implementations and provide their own. We have
an internal BoringSSL-based in-kernel crypto driver (which I hope to
open source one day) which avoids this problem. I remember there was
also some work to expose TPMs through the keyrings API, which would
solve this problem as well [3]. In general this API allows adopting
various platform crypto chips very easily and should be encouraged. I
made a presentation explaining why this API is much better for TPMs,
for example, rather than directly using /dev/tpm from userspace [4].

On the topic of better RSA implementation: last year we've been
working with folks from a company called Cryspen with the hope to
produce better and even formally-verified RSA and ECDSA
implementations for the Linux kernel (based on their HACL open source
library). We got pretty good results [5] for RSA: tl;dr signing is
faster than the current in-kernel code, but verification is slower
(not a problem as we can use verification from the in-kernel
implementation as we don't care about side channels there).
Unfortunately the work was deprioritised this year, but if there is
enough interest from the kernel community (and hopefully support to
make the code more "kernel-integration friendly) I can try to make a
case to re-prioritise this again.

> Personally I am not using this user-space API, so I don't really
> have a dog in this fight.  I just noticed the incorrect output
> for KEYCTL_PKEY_QUERY and thought it might be better if it's fixed.
>
> One user of this API is the Embedded Linux Library, which in turn
> is used by Intel Wireless Daemon:
>
> https://git.kernel.org/pub/scm/libs/ell/ell.git/tree/ell/key.c
> https://git.kernel.org/pub/scm/network/wireless/iwd.git/tree/src/eap-tls.c
>
> Basically IWD seems to be invoking the kernel's Key Retention Service for
> EAP authentication.  It's still maintained and known to have active users,
> so removing the user-space keyctl ABI would definitely cause breakage.
>
> I've just checked for other reverse dependencies of the "libell0" package
> on Debian, it lists "bluez" and "mptcpd" but looking at their source code
> reveals they're not using the l_key_*() functions, so they would not be
> affected by removal.
>
> There's a keyring package for go, so I suppose there may be go applications
> out there using it:
>
> https://pkg.go.dev/pault.ag/go/keyring
>
> Then there's the keyutils library...
>
> https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git
>
> ...and listing the reverse dependencies for "libkeyutils1" on Debian
> reveals a slew of packages which are using it:
>
>   gdm3 samba-libs sssd-common python3-keyutils nfs-common ndctl
>   mokutil kstart libkrb5-3 kafs-client ima-evm-utils ceph-common
>   libecryptfs1 ecryptfs-utils cifs-utils
>
> And "python3-keyutils" in turn has this reverse dependency:
>
>   udiskie
>
> Finally, folks at cloudflare praised the kernel's Key Retention Service
> and encouraged everyone to use it... :)
>
> https://blog.cloudflare.com/the-linux-kernel-key-retention-service-and-why-you-should-use-it-in-your-next-application/
>
> In short, it doesn't seem trivial to drop this user-space API.
>
> Thanks,
>
> Lukas

Thanks,
Ignat

[1]: https://heartbleed.com/
[2]: https://blog.cloudflare.com/keyless-ssl-the-nitty-gritty-technical-details/
[3]: https://lore.kernel.org/lkml/97dd7485-51bf-4e47-83ab-957710fc2182@linux.ibm.com/T/
[4]: https://youtu.be/g8b4K5FQUj8?si=yY8mkoRuyE_SKBjh
[5]: https://md.cryspen.com/cf_hacs_kernel

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Herbert Xu]

On Sun, Feb 09, 2025 at 12:29:54PM +0100, Lukas Wunner wrote:
>
> One user of this API is the Embedded Linux Library, which in turn
> is used by Intel Wireless Daemon:
> 
> https://git.kernel.org/pub/scm/libs/ell/ell.git/tree/ell/key.c
> https://git.kernel.org/pub/scm/network/wireless/iwd.git/tree/src/eap-tls.c

Surely this doesn't use the private key part of the API, does it?

While I intensely dislike the entire API being there, it's only the
private key part that I really want to remove.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Lukas Wunner]

On Mon, Feb 10, 2025 at 03:54:45PM +0800, Herbert Xu wrote:
> On Sun, Feb 09, 2025 at 12:29:54PM +0100, Lukas Wunner wrote:
> > One user of this API is the Embedded Linux Library, which in turn
> > is used by Intel Wireless Daemon:
> > 
> > https://git.kernel.org/pub/scm/libs/ell/ell.git/tree/ell/key.c
> > https://git.kernel.org/pub/scm/network/wireless/iwd.git/tree/src/eap-tls.c
> 
> Surely this doesn't use the private key part of the API, does it?

It does use the private key part:

It takes advantage of the kernel's Key Retention Service for EAP-TLS,
which generally uses mutual authentication.  E.g. clients authenticate
against a wireless hotspot.  Hence it does invoke KEYCTL_PKEY_SIGN and
KEYCTL_PKEY_ENCRYPT (with private keys, obviously).


> While I intensely dislike the entire API being there, it's only the
> private key part that I really want to remove.

Note that the patches proposed here only touch the KEYCTL_PKEY_QUERY
interface, which is used for public keys as well.

Thanks,

Lukas

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Lukas Wunner]

On Mon, Feb 10, 2025 at 07:53:57PM +0100, Lukas Wunner wrote:
> It takes advantage of the kernel's Key Retention Service for EAP-TLS,
> which generally uses mutual authentication.  E.g. clients authenticate
> against a wireless hotspot.  Hence it does invoke KEYCTL_PKEY_SIGN and
> KEYCTL_PKEY_ENCRYPT (with private keys, obviously).

Sorry, I meant KEYCTL_PKEY_DECRYPT.
                           ^^

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Herbert Xu]

On Mon, Feb 10, 2025 at 07:53:57PM +0100, Lukas Wunner wrote:
>
> It does use the private key part:
> 
> It takes advantage of the kernel's Key Retention Service for EAP-TLS,
> which generally uses mutual authentication.  E.g. clients authenticate
> against a wireless hotspot.  Hence it does invoke KEYCTL_PKEY_SIGN and
> KEYCTL_PKEY_ENCRYPT (with private keys, obviously).

Well if it wishes to keep this going, then someone will have to
step up and maintain these algorithms and make them secure against
side-channel attacks.

In the absence of that, this functionality should be removed
from the kernel.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Herbert Xu]

On Mon, Feb 10, 2025 at 07:53:57PM +0100, Lukas Wunner wrote:
>
> > > https://git.kernel.org/pub/scm/libs/ell/ell.git/tree/ell/key.c
> > > https://git.kernel.org/pub/scm/network/wireless/iwd.git/tree/src/eap-tls.c
> > 
> > Surely this doesn't use the private key part of the API, does it?
> 
> It does use the private key part:
> 
> It takes advantage of the kernel's Key Retention Service for EAP-TLS,
> which generally uses mutual authentication.  E.g. clients authenticate
> against a wireless hotspot.  Hence it does invoke KEYCTL_PKEY_SIGN and
> KEYCTL_PKEY_ENCRYPT (with private keys, obviously).

Does it really? I grepped the whole iwd git tree and the only
use of private key functionality is to check that it matches
the public key, IOW it encrypts a piece of text and then decrypts
it again to check whether they match.

It doesn't make use of any other private key functionality AFAICS.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Lukas Wunner]

On Sun, Feb 16, 2025 at 12:19:44PM +0800, Herbert Xu wrote:
> On Mon, Feb 10, 2025 at 07:53:57PM +0100, Lukas Wunner wrote:
> > > > https://git.kernel.org/pub/scm/libs/ell/ell.git/tree/ell/key.c
> > > > https://git.kernel.org/pub/scm/network/wireless/iwd.git/tree/src/eap-tls.c
> > > 
> > > Surely this doesn't use the private key part of the API, does it?
> > 
> > It does use the private key part:
> > 
> > It takes advantage of the kernel's Key Retention Service for EAP-TLS,
> > which generally uses mutual authentication.  E.g. clients authenticate
> > against a wireless hotspot.  Hence it does invoke KEYCTL_PKEY_SIGN and
> > KEYCTL_PKEY_ENCRYPT (with private keys, obviously).
> 
> Does it really? I grepped the whole iwd git tree and the only
> use of private key functionality is to check that it matches
> the public key, IOW it encrypts a piece of text and then decrypts
> it again to check whether they match.
> 
> It doesn't make use of any other private key functionality AFAICS.

__eap_handle_request()                            [iwd src/eap.c]
  eap->method->handle_request()
    eap_tls_common_handle_request()               [iwd src/eap-tls-common.c]
      l_tls_handle_rx()                           [ell ell/tls-record.c]
        tls_handle_ciphertext()
          tls_handle_plaintext()
            tls_handle_message()                  [ell ell/tls.c]
              tls_handle_handshake()
                tls_handle_server_hello_done()
                  tls_send_certificate_verify()
                    tls->pending.cipher_suite->signature->sign
                      tls_rsa_sign()              [ell ell/tls-suites.c]
                        l_key_sign()              [ell ell/key.c]
                          eds_common()
                            kernel_key_eds()
                              syscall(__NR_keyctl, KEYCTL_PKEY_SIGN, ...)

... where tls_handle_server_hello_done() performs client authentication
per RFC 8446 sec 4.6.2:

  "When the client has sent the "post_handshake_auth" extension (see
   Section 4.2.6), a server MAY request client authentication at any
   time after the handshake has completed by sending a
   CertificateRequest message.  The client MUST respond with the
   appropriate Authentication messages (see Section 4.4).  If the client
   chooses to authenticate, it MUST send Certificate, CertificateVerify,
   and Finished."

   https://datatracker.ietf.org/doc/html/rfc8446#section-4.6.2

I think the best option at this point isn't to aim for removal
but to wait for Cloudflare to beat their out-of-tree implementation
(which apparently isn't susceptible to side channel attacks)
into shape so that it can be upstreamed.

Thanks,

Lukas

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Herbert Xu]

On Sun, Feb 16, 2025 at 11:45:04AM +0100, Lukas Wunner wrote:
>
> I think the best option at this point isn't to aim for removal
> but to wait for Cloudflare to beat their out-of-tree implementation
> (which apparently isn't susceptible to side channel attacks)
> into shape so that it can be upstreamed.

I don't think having a one-off fix is sufficient.  We need someone
who can maintain this for the long term.  Are you willing to do this?

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Lukas Wunner]

On Sun, Mar 02, 2025 at 03:47:50PM +0800, Herbert Xu wrote:
> On Sun, Feb 16, 2025 at 11:45:04AM +0100, Lukas Wunner wrote:
> > I think the best option at this point isn't to aim for removal
> > but to wait for Cloudflare to beat their out-of-tree implementation
> > (which apparently isn't susceptible to side channel attacks)
> > into shape so that it can be upstreamed.
> 
> I don't think having a one-off fix is sufficient.  We need someone
> who can maintain this for the long term.  Are you willing to do this?

In principle, yes.

Which files are we talking about exactly?

Thanks,

Lukas

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Herbert Xu]

On Sun, Mar 02, 2025 at 10:25:34AM +0100, Lukas Wunner wrote:
>
> In principle, yes.

Great!

> Which files are we talking about exactly?

So it's basically everything under crypto/asymmetric_keys + the
algorithms that they use.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Lukas Wunner]

Hi Herbert,

patches [3/4] and [4/4] of this series have not been applied and
are marked "Changes Requested" in patchwork...

https://patchwork.kernel.org/project/linux-crypto/patch/3d74d6134f4f87a90ebe0a37cb06c6ec144ceef7.1738521533.git.lukas@wunner.de/

https://patchwork.kernel.org/project/linux-crypto/patch/c9d465b449b6ba2e4a59b3480119076ba1138ded.1738521533.git.lukas@wunner.de/

...however it's unclear to me what needs to be changed in order to
make them acceptable.  I think the objection was that asymmetric keys
need to be maintained, but that's since been addressed.

Are there further objections?  Should I resend?

Thanks!

Lukas

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Herbert Xu]

On Sat, Mar 15, 2025 at 03:37:40PM +0100, Lukas Wunner wrote:
> Hi Herbert,
> 
> patches [3/4] and [4/4] of this series have not been applied and
> are marked "Changes Requested" in patchwork...
> 
> https://patchwork.kernel.org/project/linux-crypto/patch/3d74d6134f4f87a90ebe0a37cb06c6ec144ceef7.1738521533.git.lukas@wunner.de/
> 
> https://patchwork.kernel.org/project/linux-crypto/patch/c9d465b449b6ba2e4a59b3480119076ba1138ded.1738521533.git.lukas@wunner.de/
> 
> ...however it's unclear to me what needs to be changed in order to
> make them acceptable.  I think the objection was that asymmetric keys
> need to be maintained, but that's since been addressed.
> 
> Are there further objections?  Should I resend?

I'll try to resurrect them in patchworks.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v2 3/4] crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY

[Herbert Xu]

On Mon, Mar 17, 2025 at 05:37:43PM +0800, Herbert Xu wrote:
>
> I'll try to resurrect them in patchworks.

It's not letting me do that.  So please resend.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[PATCH v2 4/4] crypto: ecdsa - Fix NIST P521 key size reported by KEYCTL_PKEY_QUERY

[Lukas Wunner]

When user space issues a KEYCTL_PKEY_QUERY system call for a NIST P521
key, the key_size is incorrectly reported as 528 bits instead of 521.

That's because the key size obtained through crypto_sig_keysize() is in
bytes and software_key_query() multiplies by 8 to yield the size in bits.
The underlying assumption is that the key size is always a multiple of 8.
With the recent addition of NIST P521, that's no longer the case.

Fix by returning the key_size in bits from crypto_sig_keysize() and
adjusting the calculations in software_key_query().

The ->key_size() callbacks of sig_alg algorithms now return the size in
bits, whereas the ->digest_size() and ->max_size() callbacks return the
size in bytes.  This matches with the units in struct keyctl_pkey_query.

Fixes: a7d45ba77d3d ("crypto: ecdsa - Register NIST P521 and extend test suite")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
---
Changes v1 -> v2:
* Use DIV_ROUND_UP_POW2() (Herbert)
* Use BITS_PER_BYTE for clarity

 crypto/asymmetric_keys/public_key.c | 8 ++++----
 crypto/ecdsa-p1363.c                | 6 ++++--
 crypto/ecdsa-x962.c                 | 5 +++--
 crypto/ecdsa.c                      | 2 +-
 crypto/ecrdsa.c                     | 2 +-
 crypto/rsassa-pkcs1.c               | 2 +-
 crypto/sig.c                        | 9 +++++++--
 include/crypto/sig.h                | 2 +-
 8 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index dd44a966947f..89dc887d2c5c 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -205,6 +205,7 @@ static int software_key_query(const struct kernel_pkey_params *params,
 			goto error_free_tfm;
 
 		len = crypto_sig_keysize(sig);
+		info->key_size = len;
 		info->max_sig_size = crypto_sig_maxsize(sig);
 		info->max_data_size = crypto_sig_digestsize(sig);
 
@@ -213,8 +214,8 @@ static int software_key_query(const struct kernel_pkey_params *params,
 			info->supported_ops |= KEYCTL_SUPPORTS_SIGN;
 
 		if (strcmp(params->encoding, "pkcs1") == 0) {
-			info->max_enc_size = len;
-			info->max_dec_size = len;
+			info->max_enc_size = len / BITS_PER_BYTE;
+			info->max_dec_size = len / BITS_PER_BYTE;
 
 			info->supported_ops |= KEYCTL_SUPPORTS_ENCRYPT;
 			if (pkey->key_is_private)
@@ -235,6 +236,7 @@ static int software_key_query(const struct kernel_pkey_params *params,
 			goto error_free_tfm;
 
 		len = crypto_akcipher_maxsize(tfm);
+		info->key_size = len * BITS_PER_BYTE;
 		info->max_sig_size = len;
 		info->max_data_size = len;
 		info->max_enc_size = len;
@@ -245,8 +247,6 @@ static int software_key_query(const struct kernel_pkey_params *params,
 			info->supported_ops |= KEYCTL_SUPPORTS_DECRYPT;
 	}
 
-	info->key_size = len * 8;
-
 	ret = 0;
 
 error_free_tfm:
diff --git a/crypto/ecdsa-p1363.c b/crypto/ecdsa-p1363.c
index 4454f1f8f33f..e0c55c64711c 100644
--- a/crypto/ecdsa-p1363.c
+++ b/crypto/ecdsa-p1363.c
@@ -21,7 +21,8 @@ static int ecdsa_p1363_verify(struct crypto_sig *tfm,
 			      const void *digest, unsigned int dlen)
 {
 	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
-	unsigned int keylen = crypto_sig_keysize(ctx->child);
+	unsigned int keylen = DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
+						BITS_PER_BYTE);
 	unsigned int ndigits = DIV_ROUND_UP_POW2(keylen, sizeof(u64));
 	struct ecdsa_raw_sig sig;
 
@@ -45,7 +46,8 @@ static unsigned int ecdsa_p1363_max_size(struct crypto_sig *tfm)
 {
 	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
 
-	return 2 * crypto_sig_keysize(ctx->child);
+	return 2 * DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
+				     BITS_PER_BYTE);
 }
 
 static unsigned int ecdsa_p1363_digest_size(struct crypto_sig *tfm)
diff --git a/crypto/ecdsa-x962.c b/crypto/ecdsa-x962.c
index 90a04f4b9a2f..ee71594d10a0 100644
--- a/crypto/ecdsa-x962.c
+++ b/crypto/ecdsa-x962.c
@@ -82,7 +82,7 @@ static int ecdsa_x962_verify(struct crypto_sig *tfm,
 	int err;
 
 	sig_ctx.ndigits = DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
-					    sizeof(u64));
+					    sizeof(u64) * BITS_PER_BYTE);
 
 	err = asn1_ber_decoder(&ecdsasignature_decoder, &sig_ctx, src, slen);
 	if (err < 0)
@@ -103,7 +103,8 @@ static unsigned int ecdsa_x962_max_size(struct crypto_sig *tfm)
 {
 	struct ecdsa_x962_ctx *ctx = crypto_sig_ctx(tfm);
 	struct sig_alg *alg = crypto_sig_alg(ctx->child);
-	int slen = crypto_sig_keysize(ctx->child);
+	int slen = DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
+				     BITS_PER_BYTE);
 
 	/*
 	 * Verify takes ECDSA-Sig-Value (described in RFC 5480) as input,
diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c
index 117526d15dde..a70b60a90a3c 100644
--- a/crypto/ecdsa.c
+++ b/crypto/ecdsa.c
@@ -167,7 +167,7 @@ static unsigned int ecdsa_key_size(struct crypto_sig *tfm)
 {
 	struct ecc_ctx *ctx = crypto_sig_ctx(tfm);
 
-	return DIV_ROUND_UP(ctx->curve->nbits, 8);
+	return ctx->curve->nbits;
 }
 
 static unsigned int ecdsa_digest_size(struct crypto_sig *tfm)
diff --git a/crypto/ecrdsa.c b/crypto/ecrdsa.c
index b3dd8a3ddeb7..2c0602f0cd40 100644
--- a/crypto/ecrdsa.c
+++ b/crypto/ecrdsa.c
@@ -249,7 +249,7 @@ static unsigned int ecrdsa_key_size(struct crypto_sig *tfm)
 	 * Verify doesn't need any output, so it's just informational
 	 * for keyctl to determine the key bit size.
 	 */
-	return ctx->pub_key.ndigits * sizeof(u64);
+	return ctx->pub_key.ndigits * sizeof(u64) * BITS_PER_BYTE;
 }
 
 static unsigned int ecrdsa_max_size(struct crypto_sig *tfm)
diff --git a/crypto/rsassa-pkcs1.c b/crypto/rsassa-pkcs1.c
index d01ac75635e0..94fa5e9600e7 100644
--- a/crypto/rsassa-pkcs1.c
+++ b/crypto/rsassa-pkcs1.c
@@ -301,7 +301,7 @@ static unsigned int rsassa_pkcs1_key_size(struct crypto_sig *tfm)
 {
 	struct rsassa_pkcs1_ctx *ctx = crypto_sig_ctx(tfm);
 
-	return ctx->key_size;
+	return ctx->key_size * BITS_PER_BYTE;
 }
 
 static int rsassa_pkcs1_set_pub_key(struct crypto_sig *tfm,
diff --git a/crypto/sig.c b/crypto/sig.c
index dfc7cae90802..53a3dd6fbe3f 100644
--- a/crypto/sig.c
+++ b/crypto/sig.c
@@ -102,6 +102,11 @@ static int sig_default_set_key(struct crypto_sig *tfm,
 	return -ENOSYS;
 }
 
+static unsigned int sig_default_size(struct crypto_sig *tfm)
+{
+	return DIV_ROUND_UP_POW2(crypto_sig_keysize(tfm), BITS_PER_BYTE);
+}
+
 static int sig_prepare_alg(struct sig_alg *alg)
 {
 	struct crypto_alg *base = &alg->base;
@@ -117,9 +122,9 @@ static int sig_prepare_alg(struct sig_alg *alg)
 	if (!alg->key_size)
 		return -EINVAL;
 	if (!alg->max_size)
-		alg->max_size = alg->key_size;
+		alg->max_size = sig_default_size;
 	if (!alg->digest_size)
-		alg->digest_size = alg->key_size;
+		alg->digest_size = sig_default_size;
 
 	base->cra_type = &crypto_sig_type;
 	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
diff --git a/include/crypto/sig.h b/include/crypto/sig.h
index 11024708c069..fa6dafafab3f 100644
--- a/include/crypto/sig.h
+++ b/include/crypto/sig.h
@@ -128,7 +128,7 @@ static inline void crypto_free_sig(struct crypto_sig *tfm)
 /**
  * crypto_sig_keysize() - Get key size
  *
- * Function returns the key size in bytes.
+ * Function returns the key size in bits.
  * Function assumes that the key is already set in the transformation. If this
  * function is called without a setkey or with a failed setkey, you may end up
  * in a NULL dereference.
-- 
2.43.0

Re: [PATCH v2 0/4] ecdsa KEYCTL_PKEY_QUERY fixes

[Herbert Xu]

On Sun, Feb 02, 2025 at 08:00:50PM +0100, Lukas Wunner wrote:
> For ecdsa, KEYCTL_PKEY_QUERY reports nonsensical values for
> enc/dec size and (for P521 keys) also the key size.
> Second attempt at fixing them.
> 
> Changes v1 -> v2:
> 
> * New patch [2/4] to introduce DIV_ROUND_UP_POW2(), which avoids
>   integer overflows that may occur with DIV_ROUND_UP() (Herbert)
> 
> * Amend patch [4/4] to use DIV_ROUND_UP_POW2() (Herbert)
> 
> * Amend patch [4/4] to use BITS_PER_BYTE for clarity
> 
> Link to v1:
> 
>   https://lore.kernel.org/r/cover.1735236227.git.lukas@wunner.de
> 
> Lukas Wunner (4):
>   crypto: sig - Prepare for algorithms with variable signature size
>   crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()
>   crypto: ecdsa - Fix enc/dec size reported by KEYCTL_PKEY_QUERY
>   crypto: ecdsa - Fix NIST P521 key size reported by KEYCTL_PKEY_QUERY
> 
>  crypto/asymmetric_keys/public_key.c | 22 +++++++++++-----------
>  crypto/ecc.c                        |  2 +-
>  crypto/ecdsa-p1363.c                |  8 +++++---
>  crypto/ecdsa-x962.c                 |  7 ++++---
>  crypto/ecdsa.c                      |  2 +-
>  crypto/ecrdsa.c                     |  2 +-
>  crypto/rsassa-pkcs1.c               |  4 ++--
>  crypto/sig.c                        |  9 +++++++--
>  crypto/testmgr.c                    |  7 ++++---
>  include/crypto/sig.h                |  7 ++++---
>  include/linux/math.h                | 12 ++++++++++++
>  11 files changed, 52 insertions(+), 30 deletions(-)
> 
> -- 
> 2.43.0

Patches 1-2 applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt