linux-kernel - [PATCH v2 5/6] x86/boot: Use copied boot data in __startup

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Message-Id: <20230412184502.145289-6-brgerst@gmail.com>
Date:   Wed, 12 Apr 2023 14:45:01 -0400
From:   Brian Gerst <brgerst@...il.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>, Brian Gerst <brgerst@...il.com>
Subject: [PATCH v2 5/6] x86/boot: Use copied boot data in __startup_64()

Use the copied version instead of the original real mode data.

Signed-off-by: Brian Gerst <brgerst@...il.com>
---
 arch/x86/include/asm/setup.h | 2 +-
 arch/x86/kernel/head64.c     | 4 ++--
 arch/x86/kernel/head_64.S    | 2 --
 3 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 47eac5d877a8..f6c04b137d67 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -49,7 +49,7 @@ extern unsigned long saved_video_mode;
 
 extern void reserve_standard_io_resources(void);
 extern void i386_reserve_resources(void);
-extern unsigned long __startup_64(unsigned long physaddr, struct boot_params *bp);
+extern unsigned long __startup_64(unsigned long physaddr);
 extern void startup_64_setup_env(unsigned long physbase);
 extern void early_setup_idt(void);
 extern void __init do_early_exception(struct pt_regs *regs, int trapnr);
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 9be8ce41d021..c7d3976a04d6 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -176,9 +176,9 @@ static unsigned long __head sme_postprocess_startup(struct boot_params *bp, pmdv
  * boot-time crashes. To work around this problem, every global pointer must
  * be adjusted using fixup_pointer().
  */
-unsigned long __head __startup_64(unsigned long physaddr,
-				  struct boot_params *bp)
+unsigned long __head __startup_64(unsigned long physaddr)
 {
+	struct boot_params *bp = fixup_pointer(&boot_params, physaddr);
 	unsigned long load_delta, *p;
 	unsigned long pgtable_flags;
 	pgdval_t *pgd;
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 83fb0dc97ba5..c7b2ef379f42 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -113,9 +113,7 @@ SYM_CODE_START_NOALIGN(startup_64)
 	 * programmed into CR3.
 	 */
 	leaq	_text(%rip), %rdi
-	pushq	%rsi
 	call	__startup_64
-	popq	%rsi
 
 	/* Form the CR3 value being sure to include the CR3 modifier */
 	addq	$(early_top_pgt - __START_KERNEL_map), %rax
-- 
2.39.2