[PATCH 0/9] Wire up getrandom() vDSO implementation on powerpc

[PATCH 0/9] Wire up getrandom() vDSO implementation on powerpc

[Christophe Leroy]

This series wires up getrandom() vDSO implementation on powerpc.

Tested on PPC32.

Performance on powerpc 885 (using kernel selftest):
	~# ./vdso_test_getrandom bench-single
	   vdso: 2500000 times in 7.897495392 seconds
	   libc: 2500000 times in 56.091632232 seconds
	syscall: 2500000 times in 55.704851989 seconds

Performance on powerpc 8321 (using kernel selftest):
	~# ./vdso_test_getrandom bench-single
	   vdso: 2500000 times in 2.017183250 seconds
	   libc: 2500000 times in 13.088533630 seconds
	syscall: 2500000 times in 12.952458068 seconds

Only build tested on PPC64.

It doesn't build with CONFIG_COMPAT. This is because unlike
gettimeofday.c, getrandom.c includes a lot of headers from outside
of include/vdso/ . The same work as done by
commit 8c59ab839f52 ("lib/vdso: Enable common headers") needs to
be done on lib/vdso/getrandom.c

Among the few strange things to be clarified, there is the format
on the key passed to __arch_chacha20_blocks_nostack(). In
struct vgetrandom_state it is declared as a table of u32, but in
reality it seems it is a flat storage that needs to be loaded in
reversed byte order, so it should either be defined as a table of
bytes, or as a table of __le32 but not a table of u32.

Christophe Leroy (9):
  powerpc/vdso: Don't discard rela sections
  powerpc/vdso32: Add crtsavres
  vdso: Add __arch_get_k_vdso_rng_data()
  vdso: Add missing c-getrandom-y in Makefile
  vdso: Avoid call to memset() by getrandom
  vdso: Only use MAP_DROPPABLE when VM_DROPPABLE exists
  powerpc: Add little endian variants of LHZX_BE and friends
  powerpc/vdso: Wire up getrandom() vDSO implementation
  selftests: [NOT TO BE MERGED] Modifications for testing VDSO getrandom
    implementation on PPC32

 arch/powerpc/Kconfig                          |   1 +
 arch/powerpc/include/asm/asm-compat.h         |  40 ++-
 arch/powerpc/include/asm/vdso/getrandom.h     |  61 ++++
 arch/powerpc/include/asm/vdso/vsyscall.h      |   7 +
 arch/powerpc/include/asm/vdso_datapage.h      |   2 +
 arch/powerpc/kernel/asm-offsets.c             |   1 +
 arch/powerpc/kernel/vdso/Makefile             |  44 ++-
 arch/powerpc/kernel/vdso/getrandom.S          |  62 ++++
 arch/powerpc/kernel/vdso/gettimeofday.S       |  13 -
 arch/powerpc/kernel/vdso/vdso32.lds.S         |   5 +-
 arch/powerpc/kernel/vdso/vdso64.lds.S         |   5 +-
 arch/powerpc/kernel/vdso/vgetrandom-chacha.S  | 297 ++++++++++++++++++
 arch/powerpc/kernel/vdso/vgetrandom.c         |  12 +
 arch/x86/include/asm/vdso/vsyscall.h          |   7 +
 drivers/char/random.c                         |   5 +-
 include/asm-generic/vdso/vsyscall.h           |   7 +
 include/vdso/limits.h                         |   4 +-
 lib/vdso/Makefile                             |   1 +
 lib/vdso/getrandom.c                          |  18 +-
 tools/testing/selftests/vDSO/Makefile         |   2 +-
 .../selftests/vDSO/vdso_test_getrandom.c      |   6 +-
 21 files changed, 553 insertions(+), 47 deletions(-)
 create mode 100644 arch/powerpc/include/asm/vdso/getrandom.h
 create mode 100644 arch/powerpc/kernel/vdso/getrandom.S
 create mode 100644 arch/powerpc/kernel/vdso/vgetrandom-chacha.S
 create mode 100644 arch/powerpc/kernel/vdso/vgetrandom.c

-- 
2.44.0

[PATCH 1/9] powerpc/vdso: Don't discard rela sections

[Christophe Leroy]

After building the VDSO, there is a verification that it contains
no dynamic relocation, see commit aff69273af61 ("vdso: Improve
cmd_vdso_check to check all dynamic relocations").

This verification uses readelf -r and doesn't work if rela sections
are discarded.

Fixes: 8ad57add77d3 ("powerpc/build: vdso linker warning for orphan sections")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/vdso/vdso32.lds.S | 4 +++-
 arch/powerpc/kernel/vdso/vdso64.lds.S | 4 ++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/vdso/vdso32.lds.S b/arch/powerpc/kernel/vdso/vdso32.lds.S
index 426e1ccc6971..8f57107000a2 100644
--- a/arch/powerpc/kernel/vdso/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso32.lds.S
@@ -74,6 +74,8 @@ SECTIONS
 	.got		: { *(.got) }			:text
 	.plt		: { *(.plt) }
 
+	.rela.dyn	: { *(.rela .rela*) }
+
 	_end = .;
 	__end = .;
 	PROVIDE(end = .);
@@ -87,7 +89,7 @@ SECTIONS
 		*(.branch_lt)
 		*(.data .data.* .gnu.linkonce.d.* .sdata*)
 		*(.bss .sbss .dynbss .dynsbss)
-		*(.got1 .glink .iplt .rela*)
+		*(.got1 .glink .iplt)
 	}
 }
 
diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S
index bda6c8cdd459..400819258c06 100644
--- a/arch/powerpc/kernel/vdso/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso64.lds.S
@@ -69,7 +69,7 @@ SECTIONS
 	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
 	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
 	.gcc_except_table : { *(.gcc_except_table) }
-	.rela.dyn ALIGN(8) : { *(.rela.dyn) }
+	.rela.dyn ALIGN(8) : { *(.rela .rela*) }
 
 	.got ALIGN(8)	: { *(.got .toc) }
 
@@ -86,7 +86,7 @@ SECTIONS
 		*(.data .data.* .gnu.linkonce.d.* .sdata*)
 		*(.bss .sbss .dynbss .dynsbss)
 		*(.opd)
-		*(.glink .iplt .plt .rela*)
+		*(.glink .iplt .plt)
 	}
 }
 
-- 
2.44.0

[PATCH 2/9] powerpc/vdso32: Add crtsavres

[Christophe Leroy]

Commit 08c18b63d965 ("powerpc/vdso32: Add missing _restgpr_31_x to fix
build failure") added _restgpr_31_x to the vdso for gettimeofday, but
the work on getrandom shows that we will need more of those functions.

Remove _restgpr_31_x and link in crtsavres.o so that we get all
save/restore functions when optimising the kernel for size.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/vdso/Makefile       |  5 ++++-
 arch/powerpc/kernel/vdso/gettimeofday.S | 13 -------------
 2 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index 1425b6edc66b..c07a425b8f78 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -43,6 +43,7 @@ else
 endif
 
 targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o
+targets += crtsavres-32.o
 obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
 targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o
 obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
@@ -68,7 +69,7 @@ targets += vdso64.lds
 CPPFLAGS_vdso64.lds += -P -C
 
 # link rule for the .so file, .lds has to be first
-$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o FORCE
+$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o $(obj)/crtsavres-32.o FORCE
 	$(call if_changed,vdso32ld_and_check)
 $(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o FORCE
 	$(call if_changed,vdso64ld_and_check)
@@ -76,6 +77,8 @@ $(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o
 # assembly rules for the .S files
 $(obj-vdso32): %-32.o: %.S FORCE
 	$(call if_changed_dep,vdso32as)
+$(obj)/crtsavres-32.o: %-32.o: $(srctree)/arch/powerpc/lib/crtsavres.S FORCE
+	$(call if_changed_dep,vdso32as)
 $(obj)/vgettimeofday-32.o: %-32.o: %.c FORCE
 	$(call if_changed_dep,vdso32cc)
 $(obj-vdso64): %-64.o: %.S FORCE
diff --git a/arch/powerpc/kernel/vdso/gettimeofday.S b/arch/powerpc/kernel/vdso/gettimeofday.S
index 48fc6658053a..67254ac9c8bb 100644
--- a/arch/powerpc/kernel/vdso/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso/gettimeofday.S
@@ -118,16 +118,3 @@ V_FUNCTION_END(__kernel_clock_getres)
 V_FUNCTION_BEGIN(__kernel_time)
 	cvdso_call __c_kernel_time call_time=1
 V_FUNCTION_END(__kernel_time)
-
-/* Routines for restoring integer registers, called by the compiler.  */
-/* Called with r11 pointing to the stack header word of the caller of the */
-/* function, just beyond the end of the integer restore area.  */
-#ifndef __powerpc64__
-_GLOBAL(_restgpr_31_x)
-_GLOBAL(_rest32gpr_31_x)
-	lwz	r0,4(r11)
-	lwz	r31,-4(r11)
-	mtlr	r0
-	mr	r1,r11
-	blr
-#endif
-- 
2.44.0

[PATCH 3/9] vdso: Add __arch_get_k_vdso_rng_data()

[Christophe Leroy]

_vdso_data is specific to x86 and __arch_get_k_vdso_data() is provided
so that all architectures can provide the requested pointer.

Do the same with _vdso_rng_data, provide __arch_get_k_vdso_rng_data()
and don't use x86 _vdso_rng_data directly.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/x86/include/asm/vdso/vsyscall.h | 7 +++++++
 drivers/char/random.c                | 5 +++--
 include/asm-generic/vdso/vsyscall.h  | 7 +++++++
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/vdso/vsyscall.h b/arch/x86/include/asm/vdso/vsyscall.h
index 972415a8be31..92b85189b8fe 100644
--- a/arch/x86/include/asm/vdso/vsyscall.h
+++ b/arch/x86/include/asm/vdso/vsyscall.h
@@ -22,6 +22,13 @@ struct vdso_data *__x86_get_k_vdso_data(void)
 }
 #define __arch_get_k_vdso_data __x86_get_k_vdso_data
 
+static __always_inline
+struct vdso_rng_data *__x86_get_k_vdso_rng_data(void)
+{
+	return &_vdso_rng_data;
+}
+#define __arch_get_k_vdso_rng_data __x86_get_k_vdso_rng_data
+
 /* The asm-generic header needs to be included after the definitions above */
 #include <asm-generic/vdso/vsyscall.h>
 
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 87fe61295ea1..77968309e2c2 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -59,6 +59,7 @@
 #ifdef CONFIG_VDSO_GETRANDOM
 #include <vdso/getrandom.h>
 #include <vdso/datapage.h>
+#include <vdso/vsyscall.h>
 #endif
 #include <asm/archrandom.h>
 #include <asm/processor.h>
@@ -282,7 +283,7 @@ static void crng_reseed(struct work_struct *work)
 	 * is ordered with the write above to base_crng.generation. Pairs with
 	 * the smp_rmb() before the syscall in the vDSO code.
 	 */
-	smp_store_release(&_vdso_rng_data.generation, next_gen + 1);
+	smp_store_release(&__arch_get_k_vdso_rng_data()->generation, next_gen + 1);
 #endif
 	if (!static_branch_likely(&crng_is_ready))
 		crng_init = CRNG_READY;
@@ -735,7 +736,7 @@ static void __cold _credit_init_bits(size_t bits)
 			queue_work(system_unbound_wq, &set_ready);
 		atomic_notifier_call_chain(&random_ready_notifier, 0, NULL);
 #ifdef CONFIG_VDSO_GETRANDOM
-		WRITE_ONCE(_vdso_rng_data.is_ready, true);
+		WRITE_ONCE(__arch_get_k_vdso_rng_data()->is_ready, true);
 #endif
 		wake_up_interruptible(&crng_init_wait);
 		kill_fasync(&fasync, SIGIO, POLL_IN);
diff --git a/include/asm-generic/vdso/vsyscall.h b/include/asm-generic/vdso/vsyscall.h
index c835607f78ae..d44a828e34a4 100644
--- a/include/asm-generic/vdso/vsyscall.h
+++ b/include/asm-generic/vdso/vsyscall.h
@@ -11,6 +11,13 @@ static __always_inline struct vdso_data *__arch_get_k_vdso_data(void)
 }
 #endif /* __arch_get_k_vdso_data */
 
+#ifndef __arch_get_k_vdso_rng_data
+static __always_inline struct vdso_rng_data *__arch_get_k_vdso_rng_data(void)
+{
+	return NULL;
+}
+#endif /* __arch_get_k_vdso_rng_data */
+
 #ifndef __arch_update_vsyscall
 static __always_inline void __arch_update_vsyscall(struct vdso_data *vdata,
 						   struct timekeeper *tk)
-- 
2.44.0

[PATCH 4/9] vdso: Add missing c-getrandom-y in Makefile

[Christophe Leroy]

Same as for gettimeofday CVDSO implementation, add c-getrandom-y
to ease the including of lib/vdso/getrandom.c in architectures
VDSO builds.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 lib/vdso/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/vdso/Makefile b/lib/vdso/Makefile
index 9f031eafc465..cedbf15f8087 100644
--- a/lib/vdso/Makefile
+++ b/lib/vdso/Makefile
@@ -4,6 +4,7 @@ GENERIC_VDSO_MK_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
 GENERIC_VDSO_DIR := $(dir $(GENERIC_VDSO_MK_PATH))
 
 c-gettimeofday-$(CONFIG_GENERIC_GETTIMEOFDAY) := $(addprefix $(GENERIC_VDSO_DIR), gettimeofday.c)
+c-getrandom-$(CONFIG_VDSO_GETRANDOM) := $(addprefix $(GENERIC_VDSO_DIR), getrandom.c)
 
 # This cmd checks that the vdso library does not contain dynamic relocations.
 # It has to be called after the linking of the vdso library and requires it
-- 
2.44.0

[PATCH 5/9] vdso: Avoid call to memset() by getrandom

[Christophe Leroy]

With the current implementation, __cvdso_getrandom_data() calls
memset(), which is unexpected in the VDSO.

Rewrite opaque data initialisation to avoid memset().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 lib/vdso/getrandom.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/lib/vdso/getrandom.c b/lib/vdso/getrandom.c
index b230f0b10832..425a422651de 100644
--- a/lib/vdso/getrandom.c
+++ b/lib/vdso/getrandom.c
@@ -73,11 +73,15 @@ __cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_
 	u32 counter[2] = { 0 };
 
 	if (unlikely(opaque_len == ~0UL && !buffer && !len && !flags)) {
-		*(struct vgetrandom_opaque_params *)opaque_state = (struct vgetrandom_opaque_params) {
-			.size_of_opaque_state = sizeof(*state),
-			.mmap_prot = PROT_READ | PROT_WRITE,
-			.mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS
-		};
+		struct vgetrandom_opaque_params *params = opaque_state;
+		int i;
+
+		params->size_of_opaque_state = sizeof(*state);
+		params->mmap_prot = PROT_READ | PROT_WRITE;
+		params->mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS;
+		for (i = 0; i < ARRAY_SIZE(params->reserved); i++)
+			params->reserved[i] = 0;
+
 		return 0;
 	}
 
-- 
2.44.0

[PATCH 6/9] vdso: Only use MAP_DROPPABLE when VM_DROPPABLE exists

[Christophe Leroy]

Commit 9651fcedf7b9 ("mm: add MAP_DROPPABLE for designating always
lazily freeable mappings") only adds MAP_DROPPABLE for 64 bits
architectures, so don't use it on 32 bits as it leads to ENOTSUPP
on mmap().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 lib/vdso/getrandom.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/vdso/getrandom.c b/lib/vdso/getrandom.c
index 425a422651de..11ba6dbf3b5e 100644
--- a/lib/vdso/getrandom.c
+++ b/lib/vdso/getrandom.c
@@ -78,7 +78,11 @@ __cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_
 
 		params->size_of_opaque_state = sizeof(*state);
 		params->mmap_prot = PROT_READ | PROT_WRITE;
-		params->mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS;
+		if (IS_ENABLED(CONFIG_64BIT))
+			params->mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS;
+		else
+			params->mmap_flags = MAP_PRIVATE | MAP_ANONYMOUS;
+
 		for (i = 0; i < ARRAY_SIZE(params->reserved); i++)
 			params->reserved[i] = 0;
 
-- 
2.44.0

[PATCH 7/9] powerpc: Add little endian variants of LHZX_BE and friends

[Christophe Leroy]

To support getrandom in VDSO which is based on little endian storage,
add macros equivalent to LHZX_BE for little endian accesses.

And move it outside of __powerpc64__ #ifdef so that it can also be
used for PPC32.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/include/asm/asm-compat.h | 40 +++++++++++++++++----------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/include/asm/asm-compat.h b/arch/powerpc/include/asm/asm-compat.h
index 2bc53c646ccd..ef8e79ae669a 100644
--- a/arch/powerpc/include/asm/asm-compat.h
+++ b/arch/powerpc/include/asm/asm-compat.h
@@ -25,20 +25,6 @@
 #define PPC_LR_STKOFF	16
 #define PPC_MIN_STKFRM	112
 
-#ifdef __BIG_ENDIAN__
-#define LHZX_BE	stringify_in_c(lhzx)
-#define LWZX_BE	stringify_in_c(lwzx)
-#define LDX_BE	stringify_in_c(ldx)
-#define STWX_BE	stringify_in_c(stwx)
-#define STDX_BE	stringify_in_c(stdx)
-#else
-#define LHZX_BE	stringify_in_c(lhbrx)
-#define LWZX_BE	stringify_in_c(lwbrx)
-#define LDX_BE	stringify_in_c(ldbrx)
-#define STWX_BE	stringify_in_c(stwbrx)
-#define STDX_BE	stringify_in_c(stdbrx)
-#endif
-
 #else /* 32-bit */
 
 /* operations for longs and pointers */
@@ -61,4 +47,30 @@
 
 #endif
 
+#ifdef __BIG_ENDIAN__
+#define LHZX_BE	stringify_in_c(lhzx)
+#define LWZX_BE	stringify_in_c(lwzx)
+#define LDX_BE	stringify_in_c(ldx)
+#define STWX_BE	stringify_in_c(stwx)
+#define STDX_BE	stringify_in_c(stdx)
+
+#define LHZX_LE	stringify_in_c(lhbrx)
+#define LWZX_LE	stringify_in_c(lwbrx)
+#define LDX_LE	stringify_in_c(ldbrx)
+#define STWX_LE	stringify_in_c(stwbrx)
+#define STDX_LE	stringify_in_c(stdbrx)
+#else
+#define LHZX_BE	stringify_in_c(lhbrx)
+#define LWZX_BE	stringify_in_c(lwbrx)
+#define LDX_BE	stringify_in_c(ldbrx)
+#define STWX_BE	stringify_in_c(stwbrx)
+#define STDX_BE	stringify_in_c(stdbrx)
+
+#define LHZX_LE	stringify_in_c(lhzx)
+#define LWZX_LE	stringify_in_c(lwzx)
+#define LDX_LE	stringify_in_c(ldx)
+#define STWX_LE	stringify_in_c(stwx)
+#define STDX_LE	stringify_in_c(stdx)
+#endif
+
 #endif /* _ASM_POWERPC_ASM_COMPAT_H */
-- 
2.44.0

[PATCH 8/9] powerpc/vdso: Wire up getrandom() vDSO implementation

[Christophe Leroy]

To be consistent with other VDSO functions, the function is called
__kernel_getrandom()

__arch_chacha20_blocks_nostack() fonction is implemented basically
with 32 bits operations. It performs 4 QUARTERROUND operations in
parallele. There are enough registers to avoid using the stack:

On input:
	r3: output bytes
	r4: 32-byte key input
	r5: 8-byte counter input/output
	r6: number of 64-byte blocks to write to output

During operation:
	r0: counter of blocks (initialised with r6)
	r4: Value '4' after key has been read.
	r6-r13: key
	r14-r15 : block counter
	r16-r31 : chacha state

At the end:
	r0, r6-r13: Zeroised
	r14-r31: Restored

Performance on powerpc 885 (using kernel selftest):
	~# ./vdso_test_getrandom bench-single
	   vdso: 2500000 times in 7.897495392 seconds
	   libc: 2500000 times in 56.091632232 seconds
	syscall: 2500000 times in 55.704851989 seconds

Performance on powerpc 8321 (using kernel selftest):
	~# ./vdso_test_getrandom bench-single
	   vdso: 2500000 times in 2.017183250 seconds
	   libc: 2500000 times in 13.088533630 seconds
	syscall: 2500000 times in 12.952458068 seconds

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/Kconfig                         |   1 +
 arch/powerpc/include/asm/vdso/getrandom.h    |  61 ++++
 arch/powerpc/include/asm/vdso/vsyscall.h     |   7 +
 arch/powerpc/include/asm/vdso_datapage.h     |   2 +
 arch/powerpc/kernel/asm-offsets.c            |   1 +
 arch/powerpc/kernel/vdso/Makefile            |  41 ++-
 arch/powerpc/kernel/vdso/getrandom.S         |  62 ++++
 arch/powerpc/kernel/vdso/vdso32.lds.S        |   1 +
 arch/powerpc/kernel/vdso/vdso64.lds.S        |   1 +
 arch/powerpc/kernel/vdso/vgetrandom-chacha.S | 297 +++++++++++++++++++
 arch/powerpc/kernel/vdso/vgetrandom.c        |  12 +
 11 files changed, 482 insertions(+), 4 deletions(-)
 create mode 100644 arch/powerpc/include/asm/vdso/getrandom.h
 create mode 100644 arch/powerpc/kernel/vdso/getrandom.S
 create mode 100644 arch/powerpc/kernel/vdso/vgetrandom-chacha.S
 create mode 100644 arch/powerpc/kernel/vdso/vgetrandom.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index d7b09b064a8a..f61cfa9ac360 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -311,6 +311,7 @@ config PPC
 	select SYSCTL_EXCEPTION_TRACE
 	select THREAD_INFO_IN_TASK
 	select TRACE_IRQFLAGS_SUPPORT
+	select VDSO_GETRANDOM			if !COMPAT
 	#
 	# Please keep this list sorted alphabetically.
 	#
diff --git a/arch/powerpc/include/asm/vdso/getrandom.h b/arch/powerpc/include/asm/vdso/getrandom.h
new file mode 100644
index 000000000000..37a678d982b4
--- /dev/null
+++ b/arch/powerpc/include/asm/vdso/getrandom.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_VDSO_GETRANDOM_H
+#define _ASM_POWERPC_VDSO_GETRANDOM_H
+
+#ifndef __ASSEMBLY__
+
+static __always_inline int do_syscall_3(const unsigned long _r0, const unsigned long _r3,
+					const unsigned long _r4, const unsigned long _r5)
+{
+	register long r0 asm("r0") = _r0;
+	register unsigned long r3 asm("r3") = _r3;
+	register unsigned long r4 asm("r4") = _r4;
+	register unsigned long r5 asm("r5") = _r5;
+	register int ret asm ("r3");
+
+	asm volatile(
+		"       sc\n"
+		"	bns+	1f\n"
+		"	neg	%0, %0\n"
+		"1:\n"
+	: "=r" (ret), "+r" (r4), "+r" (r5), "+r" (r0)
+	: "r" (r3)
+	: "memory", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "cr0", "ctr");
+
+	return ret;
+}
+
+/**
+ * getrandom_syscall - Invoke the getrandom() syscall.
+ * @buffer:	Destination buffer to fill with random bytes.
+ * @len:	Size of @buffer in bytes.
+ * @flags:	Zero or more GRND_* flags.
+ * Returns:	The number of random bytes written to @buffer, or a negative value indicating an error.
+ */
+static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags)
+{
+	return do_syscall_3(__NR_getrandom, (unsigned long)buffer,
+			    (unsigned long)len, (unsigned long)flags);
+}
+
+const struct vdso_rng_data *__arch_get_vdso_rng_data(void);
+
+ssize_t __c_kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state,
+			     size_t opaque_len, const struct vdso_rng_data *vd);
+
+/**
+ * __arch_chacha20_blocks_nostack - Generate ChaCha20 stream without using the stack.
+ * @dst_bytes:	Destination buffer to hold @nblocks * 64 bytes of output.
+ * @key:	32-byte input key.
+ * @counter:	8-byte counter, read on input and updated on return.
+ * @nblocks:	Number of blocks to generate.
+ *
+ * Generates a given positive number of blocks of ChaCha20 output with nonce=0, and does not write
+ * to any stack or memory outside of the parameters passed to it, in order to mitigate stack data
+ * leaking into forked child processes.
+ */
+void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks);
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* _ASM_POWERPC_VDSO_GETRANDOM_H */
diff --git a/arch/powerpc/include/asm/vdso/vsyscall.h b/arch/powerpc/include/asm/vdso/vsyscall.h
index 48cf23f1e273..ed60a21bba40 100644
--- a/arch/powerpc/include/asm/vdso/vsyscall.h
+++ b/arch/powerpc/include/asm/vdso/vsyscall.h
@@ -17,6 +17,13 @@ struct vdso_data *__arch_get_k_vdso_data(void)
 }
 #define __arch_get_k_vdso_data __arch_get_k_vdso_data
 
+static __always_inline
+struct vdso_rng_data *__arch_get_k_vdso_rng_data(void)
+{
+	return &vdso_data->rng_data;
+}
+#define __arch_get_k_vdso_rng_data __arch_get_k_vdso_rng_data
+
 /* The asm-generic header needs to be included after the definitions above */
 #include <asm-generic/vdso/vsyscall.h>
 
diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h
index a585c8e538ff..e17500c5237e 100644
--- a/arch/powerpc/include/asm/vdso_datapage.h
+++ b/arch/powerpc/include/asm/vdso_datapage.h
@@ -83,6 +83,7 @@ struct vdso_arch_data {
 	__u32 compat_syscall_map[SYSCALL_MAP_SIZE];	/* Map of compat syscalls */
 
 	struct vdso_data data[CS_BASES];
+	struct vdso_rng_data rng_data;
 };
 
 #else /* CONFIG_PPC64 */
@@ -95,6 +96,7 @@ struct vdso_arch_data {
 	__u32 syscall_map[SYSCALL_MAP_SIZE]; /* Map of syscalls */
 	__u32 compat_syscall_map[0];	/* No compat syscalls on PPC32 */
 	struct vdso_data data[CS_BASES];
+	struct vdso_rng_data rng_data;
 };
 
 #endif /* CONFIG_PPC64 */
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 23733282de4d..eedb2e04c785 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -335,6 +335,7 @@ int main(void)
 
 	/* datapage offsets for use by vdso */
 	OFFSET(VDSO_DATA_OFFSET, vdso_arch_data, data);
+	OFFSET(VDSO_RNG_DATA_OFFSET, vdso_arch_data, rng_data);
 	OFFSET(CFG_TB_TICKS_PER_SEC, vdso_arch_data, tb_ticks_per_sec);
 #ifdef CONFIG_PPC64
 	OFFSET(CFG_ICACHE_BLOCKSZ, vdso_arch_data, icache_block_size);
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index c07a425b8f78..b380af35001a 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -8,6 +8,9 @@ include $(srctree)/lib/vdso/Makefile
 obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o note-32.o getcpu-32.o
 obj-vdso64 = sigtramp64-64.o gettimeofday-64.o datapage-64.o cacheflush-64.o note-64.o getcpu-64.o
 
+obj-vdso32 += getrandom-32.o vgetrandom-chacha-32.o
+obj-vdso64 += getrandom-64.o vgetrandom-chacha-64.o
+
 ifneq ($(c-gettimeofday-y),)
   CFLAGS_vgettimeofday-32.o += -include $(c-gettimeofday-y)
   CFLAGS_vgettimeofday-32.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
@@ -34,6 +37,32 @@ ifneq ($(c-gettimeofday-y),)
   CFLAGS_vgettimeofday-64.o += $(call cc-option, -ffixed-r30)
 endif
 
+ifneq ($(c-getrandom-y),)
+  CFLAGS_vgetrandom-32.o += -include $(c-getrandom-y)
+  CFLAGS_vgetrandom-32.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
+  CFLAGS_vgetrandom-32.o += $(call cc-option, -fno-stack-protector)
+  CFLAGS_vgetrandom-32.o += -DDISABLE_BRANCH_PROFILING
+  CFLAGS_vgetrandom-32.o += -ffreestanding -fasynchronous-unwind-tables
+  CFLAGS_REMOVE_vgetrandom-32.o = $(CC_FLAGS_FTRACE)
+  CFLAGS_REMOVE_vgetrandom-32.o += -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc
+  # This flag is supported by clang for 64-bit but not 32-bit so it will cause
+  # an unused command line flag warning for this file.
+  ifdef CONFIG_CC_IS_CLANG
+  CFLAGS_REMOVE_vgetrandom-32.o += -fno-stack-clash-protection
+  endif
+  CFLAGS_vgetrandom-64.o += -include $(c-getrandom-y)
+  CFLAGS_vgetrandom-64.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
+  CFLAGS_vgetrandom-64.o += $(call cc-option, -fno-stack-protector)
+  CFLAGS_vgetrandom-64.o += -DDISABLE_BRANCH_PROFILING
+  CFLAGS_vgetrandom-64.o += -ffreestanding -fasynchronous-unwind-tables
+  CFLAGS_REMOVE_vgetrandom-64.o = $(CC_FLAGS_FTRACE)
+# Go prior to 1.16.x assumes r30 is not clobbered by any VDSO code. That used to be true
+# by accident when the VDSO was hand-written asm code, but may not be now that the VDSO is
+# compiler generated. To avoid breaking Go tell GCC not to use r30. Impact on code
+# generation is minimal, it will just use r29 instead.
+  CFLAGS_vgetrandom-64.o += $(call cc-option, -ffixed-r30)
+endif
+
 # Build rules
 
 ifdef CROSS32_COMPILE
@@ -42,10 +71,10 @@ else
     VDSOCC := $(CC)
 endif
 
-targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o
+targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o vgetrandom-32.o
 targets += crtsavres-32.o
 obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
-targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o
+targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o vgetrandom-64.o
 obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
 
 ccflags-y := -fno-common -fno-builtin
@@ -69,9 +98,9 @@ targets += vdso64.lds
 CPPFLAGS_vdso64.lds += -P -C
 
 # link rule for the .so file, .lds has to be first
-$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o $(obj)/crtsavres-32.o FORCE
+$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o $(obj)/vgetrandom-32.o $(obj)/crtsavres-32.o FORCE
 	$(call if_changed,vdso32ld_and_check)
-$(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o FORCE
+$(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o $(obj)/vgetrandom-64.o FORCE
 	$(call if_changed,vdso64ld_and_check)
 
 # assembly rules for the .S files
@@ -81,10 +110,14 @@ $(obj)/crtsavres-32.o: %-32.o: $(srctree)/arch/powerpc/lib/crtsavres.S FORCE
 	$(call if_changed_dep,vdso32as)
 $(obj)/vgettimeofday-32.o: %-32.o: %.c FORCE
 	$(call if_changed_dep,vdso32cc)
+$(obj)/vgetrandom-32.o: %-32.o: %.c FORCE
+	$(call if_changed_dep,vdso32cc)
 $(obj-vdso64): %-64.o: %.S FORCE
 	$(call if_changed_dep,vdso64as)
 $(obj)/vgettimeofday-64.o: %-64.o: %.c FORCE
 	$(call if_changed_dep,cc_o_c)
+$(obj)/vgetrandom-64.o: %-64.o: %.c FORCE
+	$(call if_changed_dep,cc_o_c)
 
 # Generate VDSO offsets using helper script
 gen-vdso32sym := $(src)/gen_vdso32_offsets.sh
diff --git a/arch/powerpc/kernel/vdso/getrandom.S b/arch/powerpc/kernel/vdso/getrandom.S
new file mode 100644
index 000000000000..e196a61a6634
--- /dev/null
+++ b/arch/powerpc/kernel/vdso/getrandom.S
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Userland implementation of getrandom() for processes
+ * for use in the vDSO
+ *
+ * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France
+ */
+#include <asm/processor.h>
+#include <asm/ppc_asm.h>
+#include <asm/vdso.h>
+#include <asm/vdso_datapage.h>
+#include <asm/asm-offsets.h>
+#include <asm/unistd.h>
+
+/*
+ * The macro sets two stack frames, one for the caller and one for the callee
+ * because there are no requirement for the caller to set a stack frame when
+ * calling VDSO so it may have omitted to set one, especially on PPC64
+ */
+
+.macro cvdso_call funct
+  .cfi_startproc
+	PPC_STLU	r1, -PPC_MIN_STKFRM(r1)
+  .cfi_adjust_cfa_offset PPC_MIN_STKFRM
+	mflr		r0
+	PPC_STLU	r1, -PPC_MIN_STKFRM(r1)
+  .cfi_adjust_cfa_offset PPC_MIN_STKFRM
+	PPC_STL		r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
+  .cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF
+#ifdef __powerpc64__
+	PPC_STL		r2, PPC_MIN_STKFRM + STK_GOT(r1)
+  .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT
+#endif
+	get_datapage	r8
+	addi		r8, r8, VDSO_RNG_DATA_OFFSET
+#ifdef __powerpc64__
+	bl		CFUNC(DOTSYM(\funct))
+#else
+	bl		\funct
+#endif
+	PPC_LL		r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
+#ifdef __powerpc64__
+	PPC_LL		r2, PPC_MIN_STKFRM + STK_GOT(r1)
+  .cfi_restore r2
+#endif
+	cmpwi		r3, 0
+	mtlr		r0
+	addi		r1, r1, 2 * PPC_MIN_STKFRM
+  .cfi_restore lr
+  .cfi_def_cfa_offset 0
+	crclr		so
+	bgelr+
+	crset		so
+	neg		r3, r3
+	blr
+  .cfi_endproc
+.endm
+
+	.text
+V_FUNCTION_BEGIN(__kernel_getrandom)
+	cvdso_call __c_kernel_getrandom
+V_FUNCTION_END(__kernel_getrandom)
diff --git a/arch/powerpc/kernel/vdso/vdso32.lds.S b/arch/powerpc/kernel/vdso/vdso32.lds.S
index 8f57107000a2..7b41d5d256e8 100644
--- a/arch/powerpc/kernel/vdso/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso32.lds.S
@@ -130,6 +130,7 @@ VERSION
 #if defined(CONFIG_PPC64) || !defined(CONFIG_SMP)
 		__kernel_getcpu;
 #endif
+		__kernel_getrandom;
 
 	local: *;
 	};
diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S
index 400819258c06..9481e4b892ed 100644
--- a/arch/powerpc/kernel/vdso/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso64.lds.S
@@ -123,6 +123,7 @@ VERSION
 		__kernel_sigtramp_rt64;
 		__kernel_getcpu;
 		__kernel_time;
+		__kernel_getrandom;
 
 	local: *;
 	};
diff --git a/arch/powerpc/kernel/vdso/vgetrandom-chacha.S b/arch/powerpc/kernel/vdso/vgetrandom-chacha.S
new file mode 100644
index 000000000000..355594f814e0
--- /dev/null
+++ b/arch/powerpc/kernel/vdso/vgetrandom-chacha.S
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France
+ */
+
+#include <linux/linkage.h>
+
+#include <asm/ppc_asm.h>
+
+.macro quarterround4 a1 b1 c1 d1 a2 b2 c2 d2 a3 b3 c3 d3 a4 b4 c4 d4
+	add	\a1, \a1, \b1
+	add	\a2, \a2, \b2
+	add	\a3, \a3, \b3
+	add	\a4, \a4, \b4
+	xor	\d1, \d1, \a1
+	xor	\d2, \d2, \a2
+	xor	\d3, \d3, \a3
+	xor	\d4, \d4, \a4
+	rotlwi	\d1, \d1, 16
+	rotlwi	\d2, \d2, 16
+	rotlwi	\d3, \d3, 16
+	rotlwi	\d4, \d4, 16
+	add	\c1, \c1, \d1
+	add	\c2, \c2, \d2
+	add	\c3, \c3, \d3
+	add	\c4, \c4, \d4
+	xor	\b1, \b1, \c1
+	xor	\b2, \b2, \c2
+	xor	\b3, \b3, \c3
+	xor	\b4, \b4, \c4
+	rotlwi	\b1, \b1, 12
+	rotlwi	\b2, \b2, 12
+	rotlwi	\b3, \b3, 12
+	rotlwi	\b4, \b4, 12
+	add	\a1, \a1, \b1
+	add	\a2, \a2, \b2
+	add	\a3, \a3, \b3
+	add	\a4, \a4, \b4
+	xor	\d1, \d1, \a1
+	xor	\d2, \d2, \a2
+	xor	\d3, \d3, \a3
+	xor	\d4, \d4, \a4
+	rotlwi	\d1, \d1, 8
+	rotlwi	\d2, \d2, 8
+	rotlwi	\d3, \d3, 8
+	rotlwi	\d4, \d4, 8
+	add	\c1, \c1, \d1
+	add	\c2, \c2, \d2
+	add	\c3, \c3, \d3
+	add	\c4, \c4, \d4
+	xor	\b1, \b1, \c1
+	xor	\b2, \b2, \c2
+	xor	\b3, \b3, \c3
+	xor	\b4, \b4, \c4
+	rotlwi	\b1, \b1, 7
+	rotlwi	\b2, \b2, 7
+	rotlwi	\b3, \b3, 7
+	rotlwi	\b4, \b4, 7
+.endm
+
+#define QUARTERROUND4(a1,b1,c1,d1,a2,b2,c2,d2,a3,b3,c3,d3,a4,b4,c4,d4) quarterround4 16+a1 16+b1 16+c1 16+d1 16+a2 16+b2 16+c2 16+d2 16+a3 16+b3 16+c3 16+d3 16+a4 16+b4 16+c4 16+d4
+
+/*
+ * Very basic 32 bits implementation of ChaCha20. Produces a given positive number
+ * of blocks of output with a nonce of 0, taking an input key and 8-byte
+ * counter. Importantly does not spill to the stack. Its arguments are:
+ *
+ *	r3: output bytes
+ *	r4: 32-byte key input
+ *	r5: 8-byte counter input/output
+ *	r6: number of 64-byte blocks to write to output
+ *
+ *	r0: counter of blocks (initialised with r6)
+ *	r4: Value '4' after key has been read.
+ *	r6-r13: key
+ *	r14-r15 : counter
+ *	r16-r31 : state
+ */
+SYM_FUNC_START(__arch_chacha20_blocks_nostack)
+#ifdef __powerpc64__
+	std	r14,-144(r1)
+	std	r15,-136(r1)
+	std	r16,-128(r1)
+	std	r17,-120(r1)
+	std	r18,-112(r1)
+	std	r19,-104(r1)
+	std	r20,-96(r1)
+	std	r21,-88(r1)
+	std	r22,-80(r1)
+	std	r23,-72(r1)
+	std	r24,-64(r1)
+	std	r25,-56(r1)
+	std	r26,-48(r1)
+	std	r27,-40(r1)
+	std	r28,-32(r1)
+	std	r29,-24(r1)
+	std	r30,-16(r1)
+	std	r31,-8(r1)
+#else
+	stwu	r1, -96(r1)
+#if defined(CONFIG_CPU_LITTLE_ENDIAN)
+	stw	r14,24(r1)
+	stw	r15,28(r1)
+	stw	r16,32(r1)
+	stw	r17,36(r1)
+	stw	r18,40(r1)
+	stw	r19,44(r1)
+	stw	r20,48(r1)
+	stw	r21,52(r1)
+	stw	r22,56(r1)
+	stw	r23,60(r1)
+	stw	r24,64(r1)
+	stw	r25,68(r1)
+	stw	r26,72(r1)
+	stw	r27,76(r1)
+	stw	r28,80(r1)
+	stw	r29,84(r1)
+	stw	r30,88(r1)
+	stw	r31,92(r1)
+#else
+	stmw	r14, 24(r1)
+#endif
+#endif
+	mr	r0, r6
+
+	li	r31, 4
+
+	LWZX_LE	r6, 0, r4
+	LWZX_LE	r7, r31, r4
+	addi	r4, r4, 8
+	LWZX_LE	r8, 0, r4
+	LWZX_LE	r9, r31, r4
+	addi	r4, r4, 8
+	LWZX_LE	r10, 0, r4
+	LWZX_LE	r11, r31, r4
+	addi	r4, r4, 8
+	LWZX_LE	r12, 0, r4
+	LWZX_LE	r13, r31, r4
+
+	li	r4, 4
+
+#ifdef __powerpc64__
+	LDX_LE	r14, 0, r5
+	srdi	r15, r14, 32
+#else
+	LWZX_LE	r14, 0, r5
+	LWZX_LE	r15, r4, r5
+#endif
+.Lblock:
+	li	r31, 10
+
+	lis	r16, 0x6170
+	lis	r17, 0x3320
+	lis	r18, 0x7962
+	lis	r19, 0x6b20
+	addi	r16, r16, 0x7865
+	addi	r17, r17, 0x646e
+	addi	r18, r18, 0x2d32
+	addi	r19, r19, 0x6574
+
+	mtctr	r31
+
+	mr	r20, r6
+	mr	r21, r7
+	mr	r22, r8
+	mr	r23, r9
+	mr	r24, r10
+	mr	r25, r11
+	mr	r26, r12
+	mr	r27, r13
+
+	mr	r28, r14
+	mr	r29, r15
+	li	r30, 0
+	li	r31, 0
+
+.Lpermute:
+	QUARTERROUND4( 0, 4, 8,12, 1, 5, 9,13, 2, 6,10,14, 3, 7,11,15)
+	QUARTERROUND4( 0, 5,10,15, 1, 6,11,12, 2, 7, 8,13, 3, 4, 9,14)
+
+	bdnz	.Lpermute
+
+	addis	r16, r16, 0x6170
+	addis	r17, r17, 0x3320
+	addis	r18, r18, 0x7962
+	addis	r19, r19, 0x6b20
+	addi	r16, r16, 0x7865
+	addi	r17, r17, 0x646e
+	addi	r18, r18, 0x2d32
+	addi	r19, r19, 0x6574
+
+	add	r20, r20, r6
+	add	r21, r21, r7
+	add	r22, r22, r8
+	add	r23, r23, r9
+	add	r24, r24, r10
+	add	r25, r25, r11
+	add	r26, r26, r12
+	add	r27, r27, r13
+
+	add	r28, r28, r14
+	add	r29, r29, r15
+
+	STWX_LE	r16, 0, r3
+	STWX_LE	r17, r4, r3
+	addi	r3, r3, 8
+	STWX_LE	r18, 0, r3
+	STWX_LE	r19, r4, r3
+	addi	r3, r3, 8
+	STWX_LE	r20, 0, r3
+	STWX_LE	r21, r4, r3
+	addi	r3, r3, 8
+	STWX_LE	r22, 0, r3
+	STWX_LE	r23, r4, r3
+	addi	r3, r3, 8
+	STWX_LE	r24, 0, r3
+	STWX_LE	r25, r4, r3
+	addi	r3, r3, 8
+	STWX_LE	r26, 0, r3
+	STWX_LE	r27, r4, r3
+	addi	r3, r3, 8
+	STWX_LE	r28, 0, r3
+	STWX_LE	r29, r4, r3
+	addi	r3, r3, 8
+	STWX_LE	r30, 0, r3
+	STWX_LE	r31, r4, r3
+	addi	r3, r3, 8
+
+#ifdef __powerpc64__
+	addi	r14, r14, 1
+	srdi	r15, r14, 32
+#else
+	addic	r14, r14, 1
+	addze	r15, r15
+#endif
+
+	subic.	r0, r0, 1
+	bne	.Lblock
+
+	STWX_LE	r14, 0, r5
+	STWX_LE	r15, r4, r5
+
+	li	r6, 0
+	li	r7, 0
+	li	r8, 0
+	li	r9, 0
+	li	r10, 0
+	li	r11, 0
+	li	r12, 0
+	li	r13, 0
+
+#ifdef __powerpc64__
+	ld	r14,-144(r1)
+	ld	r15,-136(r1)
+	ld	r16,-128(r1)
+	ld	r17,-120(r1)
+	ld	r18,-112(r1)
+	ld	r19,-104(r1)
+	ld	r20,-96(r1)
+	ld	r21,-88(r1)
+	ld	r22,-80(r1)
+	ld	r23,-72(r1)
+	ld	r24,-64(r1)
+	ld	r25,-56(r1)
+	ld	r26,-48(r1)
+	ld	r27,-40(r1)
+	ld	r28,-32(r1)
+	ld	r29,-24(r1)
+	ld	r30,-16(r1)
+	ld	r31,-8(r1)
+#else
+#if defined(CONFIG_CPU_LITTLE_ENDIAN)
+	lwz	r14,24(r1)
+	lwz	r15,28(r1)
+	lwz	r16,32(r1)
+	lwz	r17,36(r1)
+	lwz	r18,40(r1)
+	lwz	r19,44(r1)
+	lwz	r20,48(r1)
+	lwz	r21,52(r1)
+	lwz	r22,56(r1)
+	lwz	r23,60(r1)
+	lwz	r24,64(r1)
+	lwz	r25,68(r1)
+	lwz	r26,72(r1)
+	lwz	r27,76(r1)
+	lwz	r28,80(r1)
+	lwz	r29,84(r1)
+	lwz	r30,88(r1)
+	lwz	r31,92(r1)
+#else
+	lmw	r14, 24(r1)
+#endif
+	addi	r1, r1, 96
+#endif
+	blr
+SYM_FUNC_END(__arch_chacha20_blocks_nostack)
diff --git a/arch/powerpc/kernel/vdso/vgetrandom.c b/arch/powerpc/kernel/vdso/vgetrandom.c
new file mode 100644
index 000000000000..f442396c3715
--- /dev/null
+++ b/arch/powerpc/kernel/vdso/vgetrandom.c
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Powerpc userspace implementations of getrandom()
+ */
+#include <linux/time.h>
+#include <linux/types.h>
+
+ssize_t __c_kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state,
+			     size_t opaque_len, const struct vdso_rng_data *vd)
+{
+       return __cvdso_getrandom_data(vd, buffer, len, flags, opaque_state, opaque_len);
+}
-- 
2.44.0

[PATCH 9/9] selftests: [NOT TO BE MERGED] Modifications for testing VDSO getrandom implementation on PPC32

[Christophe Leroy]

arch/.../entry/vdso/ is specific to x86. Every architecture has a
different path. On powerpc it is in arch/.../kernel/vdso/

vdso_test_getrandom is a bit too long with 25000000.

Something is wrong with macros INT_MAX ... :

In file included from /home/chleroy/linux-powerpc/include/linux/limits.h:7,
                 from /opt/powerpc64-e5500--glibc--stable-2024.02-1/powerpc64-buildroot-linux-gnu/sysroot/usr/include/bits/local_lim.h:38,
                 from /opt/powerpc64-e5500--glibc--stable-2024.02-1/powerpc64-buildroot-linux-gnu/sysroot/usr/include/bits/posix1_lim.h:161,
                 from /opt/powerpc64-e5500--glibc--stable-2024.02-1/powerpc64-buildroot-linux-gnu/sysroot/usr/include/limits.h:195,
                 from /opt/powerpc64-e5500--glibc--stable-2024.02-1/lib/gcc/powerpc64-buildroot-linux-gnu/12.3.0/include-fixed/limits.h:203,
                 from /opt/powerpc64-e5500--glibc--stable-2024.02-1/lib/gcc/powerpc64-buildroot-linux-gnu/12.3.0/include-fixed/syslimits.h:7,
                 from /opt/powerpc64-e5500--glibc--stable-2024.02-1/lib/gcc/powerpc64-buildroot-linux-gnu/12.3.0/include-fixed/limits.h:34,
                 from /tmp/sodium/usr/local/include/sodium/export.h:7,
                 from /tmp/sodium/usr/local/include/sodium/crypto_stream_chacha20.h:14,
                 from vdso_test_chacha.c:6:
/opt/powerpc64-e5500--glibc--stable-2024.02-1/powerpc64-buildroot-linux-gnu/sysroot/usr/include/bits/xopen_lim.h:99:6: error: missing binary operator before token "("
   99 | # if INT_MAX == 32767
      |      ^~~~~~~
/opt/powerpc64-e5500--glibc--stable-2024.02-1/powerpc64-buildroot-linux-gnu/sysroot/usr/include/bits/xopen_lim.h:102:7: error: missing binary operator before token "("
  102 | #  if INT_MAX == 2147483647
      |       ^~~~~~~
/opt/powerpc64-e5500--glibc--stable-2024.02-1/powerpc64-buildroot-linux-gnu/sysroot/usr/include/bits/xopen_lim.h:126:6: error: missing binary operator before token "("
  126 | # if LONG_MAX == 2147483647
      |      ^~~~~~~~

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 include/vdso/limits.h                              | 4 ++--
 tools/testing/selftests/vDSO/Makefile              | 2 +-
 tools/testing/selftests/vDSO/vdso_test_getrandom.c | 6 +++---
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/vdso/limits.h b/include/vdso/limits.h
index 0197888ad0e0..b0459332e45f 100644
--- a/include/vdso/limits.h
+++ b/include/vdso/limits.h
@@ -5,10 +5,10 @@
 #define USHRT_MAX	((unsigned short)~0U)
 #define SHRT_MAX	((short)(USHRT_MAX >> 1))
 #define SHRT_MIN	((short)(-SHRT_MAX - 1))
-#define INT_MAX		((int)(~0U >> 1))
+#define INT_MAX		2147483647
 #define INT_MIN		(-INT_MAX - 1)
 #define UINT_MAX	(~0U)
-#define LONG_MAX	((long)(~0UL >> 1))
+#define LONG_MAX	2147483647
 #define LONG_MIN	(-LONG_MAX - 1)
 #define ULONG_MAX	(~0UL)
 #define LLONG_MAX	((long long)(~0ULL >> 1))
diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index 3de8e7e052ae..8010e7be66c6 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -40,7 +40,7 @@ $(OUTPUT)/vdso_test_getrandom: parse_vdso.c
 $(OUTPUT)/vdso_test_getrandom: CFLAGS += -isystem $(top_srcdir)/tools/include \
                                          -isystem $(top_srcdir)/include/uapi
 
-$(OUTPUT)/vdso_test_chacha: $(top_srcdir)/arch/$(ARCH)/entry/vdso/vgetrandom-chacha.S
+$(OUTPUT)/vdso_test_chacha: $(top_srcdir)/arch/$(ARCH)/kernel/vdso/vgetrandom-chacha.S
 $(OUTPUT)/vdso_test_chacha: CFLAGS += -idirafter $(top_srcdir)/tools/include \
                                       -isystem $(top_srcdir)/arch/$(ARCH)/include \
                                       -isystem $(top_srcdir)/include \
diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
index 05122425a873..f25301c9d46b 100644
--- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c
+++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
@@ -115,9 +115,9 @@ static void vgetrandom_init(void)
 		exit(KSFT_SKIP);
 	}
 	vdso_init_from_sysinfo_ehdr(sysinfo_ehdr);
-	grnd_ctx.fn = (__typeof__(grnd_ctx.fn))vdso_sym("LINUX_2.6", "__vdso_getrandom");
+	grnd_ctx.fn = (__typeof__(grnd_ctx.fn))vdso_sym("LINUX_2.6.15", "__kernel_getrandom");
 	if (!grnd_ctx.fn) {
-		printf("__vdso_getrandom is missing!\n");
+		printf("__kernel_getrandom is missing!\n");
 		exit(KSFT_FAIL);
 	}
 	if (grnd_ctx.fn(NULL, 0, 0, &grnd_ctx.params, ~0UL) != 0) {
@@ -146,7 +146,7 @@ static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags)
 	return grnd_ctx.fn(buf, len, flags, state, grnd_ctx.params.size_of_opaque_state);
 }
 
-enum { TRIALS = 25000000, THREADS = 256 };
+enum { TRIALS = 2500000, THREADS = 256 };
 
 static void *test_vdso_getrandom(void *)
 {
-- 
2.44.0

Re: [PATCH 0/9] Wire up getrandom() vDSO implementation on powerpc

[Jason A. Donenfeld]

Hi Christophe,

Thanks for this series. I'm looking forward to taking a close look at
it. I'm currently traveling until the 26th without a laptop and no
email except for lore+lei+mutt on my phone. So I'll review this in about
1 week. But I'm very happy to see it here.

On first glance, patch number 7 isn't okay. If you want this to work on
32bit, find an available bit for VM_DROPPABLE. Otherwise, just do this
64bit-only like many new features.

Jason

Re: [PATCH 0/9] Wire up getrandom() vDSO implementation on powerpc

[Jason A. Donenfeld]

On Fri, Aug 16, 2024 at 09:57:37PM +0000, Jason A. Donenfeld wrote:
> On first glance, patch number 7 isn't okay. If you want this to work on

Sorry, I meant 6.

Re: [PATCH 3/9] vdso: Add __arch_get_k_vdso_rng_data()

[kernel test robot]

Hi Christophe,

kernel test robot noticed the following build errors:

[auto build test ERROR on powerpc/next]
[also build test ERROR on powerpc/fixes crng-random/master shuah-kselftest/next shuah-kselftest/fixes linus/master v6.11-rc3 next-20240816]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Christophe-Leroy/powerpc-vdso-Don-t-discard-rela-sections/20240816-223917
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
patch link:    https://lore.kernel.org/r/a7bdbbb14d8635c1e33ada7982cf2cd1a8321e5c.1723817900.git.christophe.leroy%40csgroup.eu
patch subject: [PATCH 3/9] vdso: Add __arch_get_k_vdso_rng_data()
config: x86_64-randconfig-003-20240817 (https://download.01.org/0day-ci/archive/20240817/202408172056.OAokF1z5-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240817/202408172056.OAokF1z5-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202408172056.OAokF1z5-lkp@intel.com/

All errors (new ones prefixed by >>):

>> ld: drivers/char/random.o:arch/x86/include/asm/vdso/vsyscall.h:13: multiple definition of `_vdso_rng_data'; kernel/time/vsyscall.o:arch/x86/include/asm/vdso/vsyscall.h:13: first defined here
>> ld: drivers/char/random.o:arch/x86/include/asm/vdso/vsyscall.h:12: multiple definition of `_vdso_data'; kernel/time/vsyscall.o:arch/x86/include/asm/vdso/vsyscall.h:12: first defined here

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Re: [PATCH 3/9] vdso: Add __arch_get_k_vdso_rng_data()

[kernel test robot]

Hi Christophe,

kernel test robot noticed the following build errors:

[auto build test ERROR on powerpc/next]
[also build test ERROR on powerpc/fixes crng-random/master shuah-kselftest/next shuah-kselftest/fixes linus/master v6.11-rc3 next-20240816]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Christophe-Leroy/powerpc-vdso-Don-t-discard-rela-sections/20240816-223917
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
patch link:    https://lore.kernel.org/r/a7bdbbb14d8635c1e33ada7982cf2cd1a8321e5c.1723817900.git.christophe.leroy%40csgroup.eu
patch subject: [PATCH 3/9] vdso: Add __arch_get_k_vdso_rng_data()
config: x86_64-buildonly-randconfig-002-20240817 (https://download.01.org/0day-ci/archive/20240817/202408172143.g3Qxmakr-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240817/202408172143.g3Qxmakr-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202408172143.g3Qxmakr-lkp@intel.com/

All errors (new ones prefixed by >>):

>> ld: drivers/char/random.o:(.vvar__vdso_rng_data+0x0): multiple definition of `_vdso_rng_data'; kernel/time/vsyscall.o:(.vvar__vdso_rng_data+0x0): first defined here
>> ld: drivers/char/random.o:(.vvar__vdso_data+0x0): multiple definition of `_vdso_data'; kernel/time/vsyscall.o:(.vvar__vdso_data+0x0): first defined here

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Re: [PATCH 9/9] selftests: [NOT TO BE MERGED] Modifications for testing VDSO getrandom implementation on PPC32

[kernel test robot]

Hi Christophe,

kernel test robot noticed the following build warnings:

[auto build test WARNING on powerpc/next]
[also build test WARNING on powerpc/fixes shuah-kselftest/next shuah-kselftest/fixes linus/master v6.11-rc3]
[cannot apply to crng-random/master next-20240816]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Christophe-Leroy/powerpc-vdso-Don-t-discard-rela-sections/20240816-223917
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
patch link:    https://lore.kernel.org/r/376843e024ffa73793e8ed99b72d299c6b239799.1723817900.git.christophe.leroy%40csgroup.eu
patch subject: [PATCH 9/9] selftests: [NOT TO BE MERGED] Modifications for testing VDSO getrandom implementation on PPC32
config: x86_64-randconfig-161-20240817 (https://download.01.org/0day-ci/archive/20240818/202408180121.HB9iN2PQ-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202408180121.HB9iN2PQ-lkp@intel.com/

smatch warnings:
kernel/time/time.c:622 timespec64_to_jiffies() warn: always true condition '(sec >= ((((((((2147483647 >> 1) - 1) >> (32 - 10)) * ((1000000000 + 1000 / 2) / 1000)) / (1000000000)) << (1)) + (((((((2147483647 >> 1) - 1) >> (32 - 10)) * ((1000000000 + 1000 / 2) / 1000)) % (1000000000)) << (1)) + (1000000000) / 2) / (1000000000)) - 1)) => (0-u64max >= 0)'

vim +622 kernel/time/time.c

8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  595  
67b3f564cb1e769 kernel/time/time.c Randy Dunlap  2023-07-03  596  /**
67b3f564cb1e769 kernel/time/time.c Randy Dunlap  2023-07-03  597   * timespec64_to_jiffies - convert a timespec64 value to jiffies
67b3f564cb1e769 kernel/time/time.c Randy Dunlap  2023-07-03  598   * @value: pointer to &struct timespec64
67b3f564cb1e769 kernel/time/time.c Randy Dunlap  2023-07-03  599   *
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  600   * The TICK_NSEC - 1 rounds up the value to the next resolution.  Note
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  601   * that a remainder subtract here would not do the right thing as the
4bf07f6562a01a4 kernel/time/time.c Ingo Molnar   2021-03-22  602   * resolution values don't fall on second boundaries.  I.e. the line:
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  603   * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding.
d78c9300c51d6ce kernel/time/time.c Andrew Hunter 2014-09-04  604   * Note that due to the small error in the multiplier here, this
d78c9300c51d6ce kernel/time/time.c Andrew Hunter 2014-09-04  605   * rounding is incorrect for sufficiently large values of tv_nsec, but
d78c9300c51d6ce kernel/time/time.c Andrew Hunter 2014-09-04  606   * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're
d78c9300c51d6ce kernel/time/time.c Andrew Hunter 2014-09-04  607   * OK.
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  608   *
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  609   * Rather, we just shift the bits off the right.
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  610   *
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  611   * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  612   * value to a scaled second value.
67b3f564cb1e769 kernel/time/time.c Randy Dunlap  2023-07-03  613   *
67b3f564cb1e769 kernel/time/time.c Randy Dunlap  2023-07-03  614   * Return: jiffies value
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  615   */
751addac78b6f20 kernel/time/time.c Arnd Bergmann 2019-10-24  616  unsigned long
751addac78b6f20 kernel/time/time.c Arnd Bergmann 2019-10-24  617  timespec64_to_jiffies(const struct timespec64 *value)
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  618  {
751addac78b6f20 kernel/time/time.c Arnd Bergmann 2019-10-24  619  	u64 sec = value->tv_sec;
751addac78b6f20 kernel/time/time.c Arnd Bergmann 2019-10-24  620  	long nsec = value->tv_nsec + TICK_NSEC - 1;
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  621  
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16 @622  	if (sec >= MAX_SEC_IN_JIFFIES){
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  623  		sec = MAX_SEC_IN_JIFFIES;
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  624  		nsec = 0;
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  625  	}
9ca308506062fc4 kernel/time/time.c Baolin Wang   2015-07-29  626  	return ((sec * SEC_CONVERSION) +
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  627  		(((u64)nsec * NSEC_CONVERSION) >>
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  628  		 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
8b9365d753d9870 kernel/time.c      Ingo Molnar   2007-02-16  629  

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