@@ -60,6 +60,7 @@ SYM_CODE_START_NOALIGN(startup_64)
* compiled to run at we first fixup the physical addresses in our page
* tables and then reload them.
*/
+ mov %rsi, %r15 /* Preserve boot_params pointer */
/* Set up the stack for verify_cpu() */
leaq (__end_init_task - PTREGS_SIZE)(%rip), %rsp
@@ -73,9 +74,7 @@ SYM_CODE_START_NOALIGN(startup_64)
shrq $32, %rdx
wrmsr
- pushq %rsi
call startup_64_setup_env
- popq %rsi
#ifdef CONFIG_AMD_MEM_ENCRYPT
/*
@@ -84,10 +83,8 @@ SYM_CODE_START_NOALIGN(startup_64)
* which needs to be done before any CPUID instructions are executed in
* subsequent code.
*/
- movq %rsi, %rdi
- pushq %rsi
+ movq %r15, %rdi
call sme_enable
- popq %rsi
#endif
/* Now switch to __KERNEL_CS so IRET works reliably */
@@ -109,9 +106,7 @@ 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
@@ -200,10 +195,8 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
* %rsi carries pointer to realmode data and is callee-clobbered. Save
* and restore it.
*/
- pushq %rsi
movq %rax, %rdi
call sev_verify_cbit
- popq %rsi
/*
* Switch to new page-table
@@ -294,9 +287,7 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
wrmsr
/* Setup and Load IDT */
- pushq %rsi
call early_setup_idt
- popq %rsi
/* Check if nx is implemented */
movl $0x80000001, %eax
@@ -334,7 +325,7 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
/* rsi is pointer to real mode structure with interesting info.
pass it to C */
- movq %rsi, %rdi
+ movq %r15, %rdi
.Ljump_to_C_code:
/*
Instead of pushing/popping %RSI to/from the stack every time a function is called from startup_64(), store it in a callee preserved register and grab it from there when its value is actualled needed. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- arch/x86/kernel/head_64.S | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-)