Messages in this thread Patch in this message | | | From | Lai Jiangshan <> | Subject | [PATCH V6 44/49] x86/sev: Add and use ist_vc_switch_off_ist() | Date | Fri, 26 Nov 2021 18:12:04 +0800 |
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From: Lai Jiangshan <laijs@linux.alibaba.com>
ist_vc_switch_off_ist() is the same as vc_switch_off_ist(), but it is called without CR3 or gsbase fixed. It has to call ist_paranoid_entry() by its own.
It is prepared for using C code for the other part of identry_vc and remove ASM paranoid_entry() and paranoid_exit().
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> --- arch/x86/entry/entry_64.S | 20 ++++++++++---------- arch/x86/include/asm/traps.h | 3 ++- arch/x86/kernel/traps.c | 14 +++++++++++++- 3 files changed, 25 insertions(+), 12 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 5a9738218722..b18df736b981 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -515,26 +515,26 @@ SYM_CODE_START(\asmsym) testb $3, CS(%rsp) jnz .Lfrom_usermode_switch_stack_\@ - /* - * paranoid_entry returns SWAPGS flag for paranoid_exit in EBX. - * EBX == 0 -> SWAPGS, EBX == 1 -> no SWAPGS - */ - call paranoid_entry - - UNWIND_HINT_REGS - /* * Switch off the IST stack to make it free for nested exceptions. The - * vc_switch_off_ist() function will switch back to the interrupted + * ist_vc_switch_off_ist() function will switch back to the interrupted * stack if it is safe to do so. If not it switches to the VC fall-back * stack. */ movq %rsp, %rdi /* pt_regs pointer */ - call vc_switch_off_ist + call ist_vc_switch_off_ist movq %rax, %rsp /* Switch to new stack */ UNWIND_HINT_REGS + /* + * paranoid_entry returns SWAPGS flag for paranoid_exit in EBX. + * EBX == 0 -> SWAPGS, EBX == 1 -> no SWAPGS + */ + call paranoid_entry + + UNWIND_HINT_REGS + /* Update pt_regs */ movq ORIG_RAX(%rsp), %rsi /* get error code into 2nd argument*/ movq $-1, ORIG_RAX(%rsp) /* no syscall to restart */ diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index 686461ac9803..1aefc081d763 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -16,7 +16,8 @@ asmlinkage __visible notrace struct pt_regs *fixup_bad_iret(struct pt_regs *bad_regs); asmlinkage __visible notrace struct pt_regs *error_entry(struct pt_regs *eregs); void __init trap_init(void); -asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *eregs); +asmlinkage __visible __entry_text +struct pt_regs *ist_vc_switch_off_ist(struct pt_regs *eregs); #endif #ifdef CONFIG_X86_F00F_BUG diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 4e9d306f313c..1a84587cb4c7 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -717,7 +717,7 @@ asmlinkage __visible noinstr struct pt_regs *sync_regs(struct pt_regs *eregs) } #ifdef CONFIG_AMD_MEM_ENCRYPT -asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *regs) +static noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *regs) { unsigned long sp, *stack; struct stack_info info; @@ -757,6 +757,18 @@ asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *r return regs_ret; } + +asmlinkage __visible __entry_text +struct pt_regs *ist_vc_switch_off_ist(struct pt_regs *regs) +{ + unsigned long cr3, gsbase; + + ist_paranoid_entry(&cr3, &gsbase); + regs = vc_switch_off_ist(regs); + ist_paranoid_exit(cr3, gsbase); + + return regs; +} #endif asmlinkage __visible noinstr -- 2.19.1.6.gb485710b
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