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Subject[PATCH 2/2] x86/head_64.S: Pass struct boot_params' virtual address to C
Date
From: Borislav Petkov <bp@suse.de>

... so that callees don't have to convert it and can use it directly.
Simplifies C code a bit. Cleanup comments and formatting in the
vicinity, while at it.

Also, document what phys_base really is.

No functionality change.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/kernel/head64.c | 8 ++++----
arch/x86/kernel/head_64.S | 10 +++++++---
2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 54a2372f5dbb..17ee20a9b4e4 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -118,7 +118,7 @@ static unsigned long get_cmd_line_ptr(void)

static void __init copy_bootdata(char *real_mode_data)
{
- char * command_line;
+ char *command_line;
unsigned long cmd_line_ptr;

memcpy(&boot_params, real_mode_data, sizeof boot_params);
@@ -130,7 +130,7 @@ static void __init copy_bootdata(char *real_mode_data)
}
}

-asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
+asmlinkage __visible void __init x86_64_start_kernel(char *real_mode_data)
{
int i;

@@ -163,7 +163,7 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
set_intr_gate(i, early_idt_handler_array[i]);
load_idt((const struct desc_ptr *)&idt_descr);

- copy_bootdata(__va(real_mode_data));
+ copy_bootdata(real_mode_data);

/*
* Load microcode early on BSP.
@@ -180,7 +180,7 @@ void __init x86_64_start_reservations(char *real_mode_data)
{
/* version is always not zero if it is copied */
if (!boot_params.hdr.version)
- copy_bootdata(__va(real_mode_data));
+ copy_bootdata(real_mode_data);

x86_early_init_platform_quirks();

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index ac9d327d2e42..506de36293bc 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -266,9 +266,12 @@ ENTRY(secondary_startup_64)
movl initial_gs+4(%rip),%edx
wrmsr

- /* rsi is pointer to real mode structure with interesting info.
- pass it to C */
- movq %rsi, %rdi
+ /*
+ * %rsi is pointer to real mode struct boot_params with interesting info.
+ * Pass its virtual address to C.
+ */
+ movq $__PAGE_OFFSET_BASE, %rdi
+ addq %rsi, %rdi

.Ljump_to_C_code:
/*
@@ -487,6 +490,7 @@ early_gdt_descr:
early_gdt_descr_base:
.quad INIT_PER_CPU_VAR(gdt_page)

+/* The physical address the kernel is loaded at. */
ENTRY(phys_base)
/* This must match the first entry in level2_kernel_pgt */
.quad 0x0000000000000000
--
2.11.0
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