All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org, keescook@chromium.org,
	mark.rutland@arm.com, catalin.marinas@arm.com,
	Ard Biesheuvel <ardb@kernel.org>
Subject: [RFC PATCH v2 11/18] arm64: mm: make vabits_actual a build time constant if possible
Date: Wed, 30 Mar 2022 17:41:58 +0200	[thread overview]
Message-ID: <20220330154205.2483167-12-ardb@kernel.org> (raw)
In-Reply-To: <20220330154205.2483167-1-ardb@kernel.org>

Currently, we only support 52-bit virtual addressing on 64k pages
configurations, and in all other cases, vabits_actual is guaranteed to
equal VA_BITS (== VA_BITS_MIN). So get rid of the variable entirely in
that case.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/include/asm/memory.h | 4 ++++
 arch/arm64/kernel/head.S        | 7 +++----
 arch/arm64/mm/mmu.c             | 2 ++
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 2f1a48be11cf..c989f6bf5426 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -174,7 +174,11 @@
 #include <linux/types.h>
 #include <asm/bug.h>
 
+#if VA_BITS > 48
 extern u64			vabits_actual;
+#else
+#define vabits_actual		VA_BITS
+#endif
 
 extern s64			memstart_addr;
 /* PHYS_OFFSET - the physical address of the start of memory. */
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 44e2e39046a9..836237289ffb 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -283,19 +283,18 @@ SYM_FUNC_START_LOCAL(create_idmap)
 	adrp	x0, idmap_pg_dir
 	adrp	x3, _text			// __pa(_text)
 
-#ifdef CONFIG_ARM64_VA_BITS_52
+#if (VA_BITS > 48)
 	mrs_s	x6, SYS_ID_AA64MMFR2_EL1
 	and	x6, x6, #(0xf << ID_AA64MMFR2_LVA_SHIFT)
 	mov	x5, #52
 	cbnz	x6, 1f
-#endif
 	mov	x5, #VA_BITS_MIN
 1:
 	adr_l	x6, vabits_actual
 	str	x5, [x6]
 	dmb	sy
 	dc	ivac, x6		// Invalidate potentially stale cache line
-
+#endif
 	/*
 	 * VA_BITS may be too small to allow for an ID mapping to be created
 	 * that covers system RAM if that is located sufficiently high in the
@@ -725,7 +724,7 @@ SYM_FUNC_START(__enable_mmu)
 SYM_FUNC_END(__enable_mmu)
 
 SYM_FUNC_START(__cpu_secondary_check52bitva)
-#ifdef CONFIG_ARM64_VA_BITS_52
+#if (VA_BITS > 48)
 	ldr_l	x0, vabits_actual
 	cmp	x0, #52
 	b.ne	2f
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 20dd95a750bc..8933d4f72427 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -45,8 +45,10 @@
 
 u64 idmap_t0sz = TCR_T0SZ(VA_BITS_MIN);
 
+#if (VA_BITS > 48)
 u64 __section(".mmuoff.data.write") vabits_actual;
 EXPORT_SYMBOL(vabits_actual);
+#endif
 
 u64 kimage_voffset __ro_after_init;
 EXPORT_SYMBOL(kimage_voffset);
-- 
2.30.2


WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org, keescook@chromium.org,
	mark.rutland@arm.com, catalin.marinas@arm.com,
	Ard Biesheuvel <ardb@kernel.org>
Subject: [RFC PATCH v2 11/18] arm64: mm: make vabits_actual a build time constant if possible
Date: Wed, 30 Mar 2022 17:41:58 +0200	[thread overview]
Message-ID: <20220330154205.2483167-12-ardb@kernel.org> (raw)
In-Reply-To: <20220330154205.2483167-1-ardb@kernel.org>

Currently, we only support 52-bit virtual addressing on 64k pages
configurations, and in all other cases, vabits_actual is guaranteed to
equal VA_BITS (== VA_BITS_MIN). So get rid of the variable entirely in
that case.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/include/asm/memory.h | 4 ++++
 arch/arm64/kernel/head.S        | 7 +++----
 arch/arm64/mm/mmu.c             | 2 ++
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 2f1a48be11cf..c989f6bf5426 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -174,7 +174,11 @@
 #include <linux/types.h>
 #include <asm/bug.h>
 
+#if VA_BITS > 48
 extern u64			vabits_actual;
+#else
+#define vabits_actual		VA_BITS
+#endif
 
 extern s64			memstart_addr;
 /* PHYS_OFFSET - the physical address of the start of memory. */
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 44e2e39046a9..836237289ffb 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -283,19 +283,18 @@ SYM_FUNC_START_LOCAL(create_idmap)
 	adrp	x0, idmap_pg_dir
 	adrp	x3, _text			// __pa(_text)
 
-#ifdef CONFIG_ARM64_VA_BITS_52
+#if (VA_BITS > 48)
 	mrs_s	x6, SYS_ID_AA64MMFR2_EL1
 	and	x6, x6, #(0xf << ID_AA64MMFR2_LVA_SHIFT)
 	mov	x5, #52
 	cbnz	x6, 1f
-#endif
 	mov	x5, #VA_BITS_MIN
 1:
 	adr_l	x6, vabits_actual
 	str	x5, [x6]
 	dmb	sy
 	dc	ivac, x6		// Invalidate potentially stale cache line
-
+#endif
 	/*
 	 * VA_BITS may be too small to allow for an ID mapping to be created
 	 * that covers system RAM if that is located sufficiently high in the
@@ -725,7 +724,7 @@ SYM_FUNC_START(__enable_mmu)
 SYM_FUNC_END(__enable_mmu)
 
 SYM_FUNC_START(__cpu_secondary_check52bitva)
-#ifdef CONFIG_ARM64_VA_BITS_52
+#if (VA_BITS > 48)
 	ldr_l	x0, vabits_actual
 	cmp	x0, #52
 	b.ne	2f
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 20dd95a750bc..8933d4f72427 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -45,8 +45,10 @@
 
 u64 idmap_t0sz = TCR_T0SZ(VA_BITS_MIN);
 
+#if (VA_BITS > 48)
 u64 __section(".mmuoff.data.write") vabits_actual;
 EXPORT_SYMBOL(vabits_actual);
+#endif
 
 u64 kimage_voffset __ro_after_init;
 EXPORT_SYMBOL(kimage_voffset);
-- 
2.30.2


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2022-03-30 15:42 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-30 15:41 [RFC PATCH v2 00/18] arm64: efi: leave MMU and caches on at boot Ard Biesheuvel
2022-03-30 15:41 ` Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 01/18] arm64: head: drop idmap_ptrs_per_pgd Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 02/18] arm64: head: split off idmap creation code Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 03/18] arm64: kernel: drop unnecessary PoC cache clean+invalidate Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 04/18] arm64: head: cover entire kernel image in ID map Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 05/18] arm64: head: factor out TTBR1 assignment into a macro Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 06/18] arm64: head: populate kernel page tables with MMU and caches on Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 07/18] arm64: kaslr: deal with init called with VA randomization enabled Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 08/18] arm64: setup: defer R/O remapping of FDT Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 09/18] arm64: head: relocate kernel only a single time if KASLR is enabled Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 10/18] arm64: head: record the MMU state at primary entry Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:41 ` Ard Biesheuvel [this message]
2022-03-30 15:41   ` [RFC PATCH v2 11/18] arm64: mm: make vabits_actual a build time constant if possible Ard Biesheuvel
2022-03-30 15:41 ` [RFC PATCH v2 12/18] arm64: head: avoid cache invalidation when entering with the MMU on Ard Biesheuvel
2022-03-30 15:41   ` Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 13/18] arm64: head: record CPU boot mode after enabling the MMU Ard Biesheuvel
2022-03-30 15:42   ` Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 14/18] arm64: head: clean the ID map page to the PoC Ard Biesheuvel
2022-03-30 15:42   ` Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 15/18] arm64: lds: move idmap_pg_dir out of .rodata Ard Biesheuvel
2022-03-30 15:42   ` Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 16/18] efi: libstub: pass image handle to handle_kernel_image() Ard Biesheuvel
2022-03-30 15:42   ` Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 17/18] efi/arm64: libstub: run image in place if randomized by the loader Ard Biesheuvel
2022-03-30 15:42   ` Ard Biesheuvel
2022-03-30 15:42 ` [RFC PATCH v2 18/18] arm64: efi/libstub: enter with the MMU on if executing in place Ard Biesheuvel
2022-03-30 15:42   ` Ard Biesheuvel
2022-03-31 15:37 ` [RFC PATCH v2 00/18] arm64: efi: leave MMU and caches on at boot Mark Rutland
2022-03-31 15:37   ` Mark Rutland
2022-03-31 16:20   ` Ard Biesheuvel
2022-03-31 16:20     ` Ard Biesheuvel

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220330154205.2483167-12-ardb@kernel.org \
    --to=ardb@kernel.org \
    --cc=catalin.marinas@arm.com \
    --cc=keescook@chromium.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-efi@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.