linux-kernel - [PATCH v6 09/15] x86/percpu/64: Remove fixed_percpu

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Message-ID: <20250123190747.745588-10-brgerst@gmail.com>
Date: Thu, 23 Jan 2025 14:07:41 -0500
From: Brian Gerst <brgerst@...il.com>
To: linux-kernel@...r.kernel.org,
	x86@...nel.org
Cc: Ingo Molnar <mingo@...nel.org>,
	"H . Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Borislav Petkov <bp@...en8.de>,
	Ard Biesheuvel <ardb@...nel.org>,
	Uros Bizjak <ubizjak@...il.com>,
	Brian Gerst <brgerst@...il.com>
Subject: [PATCH v6 09/15] x86/percpu/64: Remove fixed_percpu_data

Now that the stack protector canary value is a normal percpu variable,
fixed_percpu_data is unused and can be removed.

Signed-off-by: Brian Gerst <brgerst@...il.com>
Reviewed-by: Ard Biesheuvel <ardb@...nel.org>
Reviewed-by: Uros Bizjak <ubizjak@...il.com>
---
 arch/x86/include/asm/processor.h | 8 --------
 arch/x86/kernel/cpu/common.c     | 4 ----
 arch/x86/kernel/vmlinux.lds.S    | 1 -
 arch/x86/tools/relocs.c          | 1 -
 4 files changed, 14 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b8fee88dac3d..b3d153730f63 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -421,14 +421,6 @@ struct irq_stack {
 } __aligned(IRQ_STACK_SIZE);
 
 #ifdef CONFIG_X86_64
-struct fixed_percpu_data {
-	char		gs_base[40];
-	unsigned long	reserved;
-};
-
-DECLARE_PER_CPU_FIRST(struct fixed_percpu_data, fixed_percpu_data) __visible;
-DECLARE_INIT_PER_CPU(fixed_percpu_data);
-
 static inline unsigned long cpu_kernelmode_gs_base(int cpu)
 {
 #ifdef CONFIG_SMP
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index b71178f0ed6c..8b49b1338f76 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -2023,10 +2023,6 @@ EXPORT_PER_CPU_SYMBOL(pcpu_hot);
 EXPORT_PER_CPU_SYMBOL(const_pcpu_hot);
 
 #ifdef CONFIG_X86_64
-DEFINE_PER_CPU_FIRST(struct fixed_percpu_data,
-		     fixed_percpu_data) __aligned(PAGE_SIZE) __visible;
-EXPORT_PER_CPU_SYMBOL_GPL(fixed_percpu_data);
-
 static void wrmsrl_cstar(unsigned long val)
 {
 	/*
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 8a598515239a..93c2fa8a7522 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -477,7 +477,6 @@ PROVIDE(__ref_stack_chk_guard = __stack_chk_guard);
  */
 #define INIT_PER_CPU(x) init_per_cpu__##x = ABSOLUTE(x)
 INIT_PER_CPU(gdt_page);
-INIT_PER_CPU(fixed_percpu_data);
 INIT_PER_CPU(irq_stack_backing_store);
 
 #ifdef CONFIG_MITIGATION_UNRET_ENTRY
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 9aebc3b18d73..a9f8bc6aaafc 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -830,7 +830,6 @@ static void percpu_init(void)
  *	__per_cpu_load
  *
  * The "gold" linker incorrectly associates:
- *	init_per_cpu__fixed_percpu_data
  *	init_per_cpu__gdt_page
  */
 static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
-- 
2.47.1