[PATCH 6/9] x86/asm/head: use a common function for starting CPUs
There are two different pieces of code for starting a CPU: start_cpu0() and the end of secondary_startup_64(). They're identical except for the stack setup. Combine the common parts into a shared start_cpu() function. Signed-off-by: Josh Poimboeuf--- arch/x86/kernel/head_64.S | 22 +++--- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index c98a559..3621ad2 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -264,13 +264,17 @@ ENTRY(secondary_startup_64) movl$MSR_GS_BASE,%ecx movlinitial_gs(%rip),%eax movlinitial_gs+4(%rip),%edx - wrmsr + wrmsr /* rsi is pointer to real mode structure with interesting info. pass it to C */ movq%rsi, %rdi - - /* Finally jump to run C code and to be on real kernel address + jmp start_cpu +ENDPROC(secondary_startup_64) + +ENTRY(start_cpu) + /* +* Jump to run C code and to be on a real kernel address. * Since we are running on identity-mapped space we have to jump * to the full 64bit address, this is only possible as indirect * jump. In addition we need to ensure %cs is set so we make this @@ -299,7 +303,7 @@ ENTRY(secondary_startup_64) pushq $__KERNEL_CS# set correct cs pushq %rax# target address in negative space lretq -ENDPROC(secondary_startup_64) +ENDPROC(start_cpu) #include "verify_cpu.S" @@ -307,15 +311,11 @@ ENDPROC(secondary_startup_64) /* * Boot CPU0 entry point. It's called from play_dead(). Everything has been set * up already except stack. We just set up stack here. Then call - * start_secondary(). + * start_secondary() via start_cpu(). */ ENTRY(start_cpu0) - movq initial_stack(%rip),%rsp - movqinitial_code(%rip),%rax - pushq $0 # fake return address to stop unwinder - pushq $__KERNEL_CS# set correct cs - pushq %rax# target address in negative space - lretq + movqinitial_stack(%rip), %rsp + jmp start_cpu ENDPROC(start_cpu0) #endif -- 2.7.4
[PATCH 6/9] x86/asm/head: use a common function for starting CPUs
There are two different pieces of code for starting a CPU: start_cpu0() and the end of secondary_startup_64(). They're identical except for the stack setup. Combine the common parts into a shared start_cpu() function. Signed-off-by: Josh Poimboeuf --- arch/x86/kernel/head_64.S | 22 +++--- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index c98a559..3621ad2 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -264,13 +264,17 @@ ENTRY(secondary_startup_64) movl$MSR_GS_BASE,%ecx movlinitial_gs(%rip),%eax movlinitial_gs+4(%rip),%edx - wrmsr + wrmsr /* rsi is pointer to real mode structure with interesting info. pass it to C */ movq%rsi, %rdi - - /* Finally jump to run C code and to be on real kernel address + jmp start_cpu +ENDPROC(secondary_startup_64) + +ENTRY(start_cpu) + /* +* Jump to run C code and to be on a real kernel address. * Since we are running on identity-mapped space we have to jump * to the full 64bit address, this is only possible as indirect * jump. In addition we need to ensure %cs is set so we make this @@ -299,7 +303,7 @@ ENTRY(secondary_startup_64) pushq $__KERNEL_CS# set correct cs pushq %rax# target address in negative space lretq -ENDPROC(secondary_startup_64) +ENDPROC(start_cpu) #include "verify_cpu.S" @@ -307,15 +311,11 @@ ENDPROC(secondary_startup_64) /* * Boot CPU0 entry point. It's called from play_dead(). Everything has been set * up already except stack. We just set up stack here. Then call - * start_secondary(). + * start_secondary() via start_cpu(). */ ENTRY(start_cpu0) - movq initial_stack(%rip),%rsp - movqinitial_code(%rip),%rax - pushq $0 # fake return address to stop unwinder - pushq $__KERNEL_CS# set correct cs - pushq %rax# target address in negative space - lretq + movqinitial_stack(%rip), %rsp + jmp start_cpu ENDPROC(start_cpu0) #endif -- 2.7.4