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[PATCH v3 3/7] x86/asm-offsets: Export struct cpuinfo_x86 layout for asm use

Ard Biesheuvel posted 7 patches 8 months, 4 weeks ago
There is a newer version of this series
[PATCH v3 3/7] x86/asm-offsets: Export struct cpuinfo_x86 layout for asm use
Posted by Ard Biesheuvel 8 months, 4 weeks ago 
From: Ard Biesheuvel <ardb@kernel.org>

Expose struct cpuinfo_x86 via asm-offsets for x86_64 too so that it will
be possible to set CPU capabilities from asm code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/x86/kernel/asm-offsets.c    | 8 ++++++++
 arch/x86/kernel/asm-offsets_32.c | 9 ---------
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index ad4ea6fb3b6c..6259b474073b 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -33,6 +33,14 @@
 
 static void __used common(void)
 {
+	OFFSET(CPUINFO_x86, cpuinfo_x86, x86);
+	OFFSET(CPUINFO_x86_vendor, cpuinfo_x86, x86_vendor);
+	OFFSET(CPUINFO_x86_model, cpuinfo_x86, x86_model);
+	OFFSET(CPUINFO_x86_stepping, cpuinfo_x86, x86_stepping);
+	OFFSET(CPUINFO_cpuid_level, cpuinfo_x86, cpuid_level);
+	OFFSET(CPUINFO_x86_capability, cpuinfo_x86, x86_capability);
+	OFFSET(CPUINFO_x86_vendor_id, cpuinfo_x86, x86_vendor_id);
+
 	BLANK();
 	OFFSET(TASK_threadsp, task_struct, thread.sp);
 #ifdef CONFIG_STACKPROTECTOR
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c
index 2b411cd00a4e..e0a292db97b2 100644
--- a/arch/x86/kernel/asm-offsets_32.c
+++ b/arch/x86/kernel/asm-offsets_32.c
@@ -12,15 +12,6 @@ void foo(void);
 
 void foo(void)
 {
-	OFFSET(CPUINFO_x86, cpuinfo_x86, x86);
-	OFFSET(CPUINFO_x86_vendor, cpuinfo_x86, x86_vendor);
-	OFFSET(CPUINFO_x86_model, cpuinfo_x86, x86_model);
-	OFFSET(CPUINFO_x86_stepping, cpuinfo_x86, x86_stepping);
-	OFFSET(CPUINFO_cpuid_level, cpuinfo_x86, cpuid_level);
-	OFFSET(CPUINFO_x86_capability, cpuinfo_x86, x86_capability);
-	OFFSET(CPUINFO_x86_vendor_id, cpuinfo_x86, x86_vendor_id);
-	BLANK();
-
 	OFFSET(PT_EBX, pt_regs, bx);
 	OFFSET(PT_ECX, pt_regs, cx);
 	OFFSET(PT_EDX, pt_regs, dx);
-- 
2.49.0.1101.gccaa498523-goog
Re: [PATCH v3 3/7] x86/asm-offsets: Export struct cpuinfo_x86 layout for asm use
Posted by Ingo Molnar 8 months, 4 weeks ago 
* Ard Biesheuvel <ardb+git@google.com> wrote:

> From: Ard Biesheuvel <ardb@kernel.org>
> 
> Expose struct cpuinfo_x86 via asm-offsets for x86_64 too so that it will
> be possible to set CPU capabilities from asm code.

Note that this title and changelog is slightly inaccurate: we don't 
really expose 'struct cpuinfo_x86', only certain fields of it. Most of 
the fields are not exported, only those that are used (or will be used) 
by asm code.

I fixed up the changelog.

Thanks,

	Ingo
[tip: x86/core] x86/asm-offsets: Export certain 'struct cpuinfo_x86' fields for 64-bit asm use too
Posted by tip-bot2 for Ard Biesheuvel 8 months, 4 weeks ago 
The following commit has been merged into the x86/core branch of tip:

Commit-ID:     25219c2578b32c96087569d074e32c8ae634d602
Gitweb:        https://git.kernel.org/tip/25219c2578b32c96087569d074e32c8ae634d602
Author:        Ard Biesheuvel <ardb@kernel.org>
AuthorDate:    Wed, 14 May 2025 12:42:46 +02:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 15 May 2025 09:12:07 +02:00

x86/asm-offsets: Export certain 'struct cpuinfo_x86' fields for 64-bit asm use too

Expose certain 'struct cpuinfo_x86' fields via asm-offsets for x86_64
too, so that it will be possible to set CPU capabilities from 64-bit
asm code.

32-bit already used these fields, so simply move those offset exports into
the unified asm-offsets.c file.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250514104242.1275040-12-ardb+git@google.com
---
 arch/x86/kernel/asm-offsets.c    |  8 ++++++++
 arch/x86/kernel/asm-offsets_32.c |  9 ---------
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index ad4ea6f..6259b47 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -33,6 +33,14 @@
 
 static void __used common(void)
 {
+	OFFSET(CPUINFO_x86, cpuinfo_x86, x86);
+	OFFSET(CPUINFO_x86_vendor, cpuinfo_x86, x86_vendor);
+	OFFSET(CPUINFO_x86_model, cpuinfo_x86, x86_model);
+	OFFSET(CPUINFO_x86_stepping, cpuinfo_x86, x86_stepping);
+	OFFSET(CPUINFO_cpuid_level, cpuinfo_x86, cpuid_level);
+	OFFSET(CPUINFO_x86_capability, cpuinfo_x86, x86_capability);
+	OFFSET(CPUINFO_x86_vendor_id, cpuinfo_x86, x86_vendor_id);
+
 	BLANK();
 	OFFSET(TASK_threadsp, task_struct, thread.sp);
 #ifdef CONFIG_STACKPROTECTOR
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c
index 2b411cd..e0a292d 100644
--- a/arch/x86/kernel/asm-offsets_32.c
+++ b/arch/x86/kernel/asm-offsets_32.c
@@ -12,15 +12,6 @@ void foo(void);
 
 void foo(void)
 {
-	OFFSET(CPUINFO_x86, cpuinfo_x86, x86);
-	OFFSET(CPUINFO_x86_vendor, cpuinfo_x86, x86_vendor);
-	OFFSET(CPUINFO_x86_model, cpuinfo_x86, x86_model);
-	OFFSET(CPUINFO_x86_stepping, cpuinfo_x86, x86_stepping);
-	OFFSET(CPUINFO_cpuid_level, cpuinfo_x86, cpuid_level);
-	OFFSET(CPUINFO_x86_capability, cpuinfo_x86, x86_capability);
-	OFFSET(CPUINFO_x86_vendor_id, cpuinfo_x86, x86_vendor_id);
-	BLANK();
-
 	OFFSET(PT_EBX, pt_regs, bx);
 	OFFSET(PT_ECX, pt_regs, cx);
 	OFFSET(PT_EDX, pt_regs, dx);

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