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-rw-r--r--arch/x86/entry/entry_64.S10
-rw-r--r--arch/x86/include/asm/irqflags.h20
-rw-r--r--arch/x86/include/asm/paravirt.h20
-rw-r--r--arch/x86/include/asm/paravirt_types.h2
-rw-r--r--arch/x86/kernel/asm-offsets_64.c1
-rw-r--r--arch/x86/kernel/paravirt.c1
-rw-r--r--arch/x86/kernel/paravirt_patch.c3
-rw-r--r--arch/x86/xen/enlighten_pv.c3
8 files changed, 13 insertions, 47 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index cad08703c4ad..a876204a73e0 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -669,7 +669,7 @@ native_irq_return_ldt:
*/
pushq %rdi /* Stash user RDI */
- SWAPGS /* to kernel GS */
+ swapgs /* to kernel GS */
SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi /* to kernel CR3 */
movq PER_CPU_VAR(espfix_waddr), %rdi
@@ -699,7 +699,7 @@ native_irq_return_ldt:
orq PER_CPU_VAR(espfix_stack), %rax
SWITCH_TO_USER_CR3_STACK scratch_reg=%rdi
- SWAPGS /* to user GS */
+ swapgs /* to user GS */
popq %rdi /* Restore user RDI */
movq %rax, %rsp
@@ -943,7 +943,7 @@ SYM_CODE_START_LOCAL(paranoid_entry)
ret
.Lparanoid_entry_swapgs:
- SWAPGS
+ swapgs
/*
* The above SAVE_AND_SWITCH_TO_KERNEL_CR3 macro doesn't do an
@@ -1001,7 +1001,7 @@ SYM_CODE_START_LOCAL(paranoid_exit)
jnz restore_regs_and_return_to_kernel
/* We are returning to a context with user GSBASE */
- SWAPGS_UNSAFE_STACK
+ swapgs
jmp restore_regs_and_return_to_kernel
SYM_CODE_END(paranoid_exit)
@@ -1426,7 +1426,7 @@ nmi_no_fsgsbase:
jnz nmi_restore
nmi_swapgs:
- SWAPGS_UNSAFE_STACK
+ swapgs
nmi_restore:
POP_REGS
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index 2dfc8d380dab..8c86edefa115 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -131,18 +131,6 @@ static __always_inline unsigned long arch_local_irq_save(void)
#define SAVE_FLAGS(x) pushfq; popq %rax
#endif
-#define SWAPGS swapgs
-/*
- * Currently paravirt can't handle swapgs nicely when we
- * don't have a stack we can rely on (such as a user space
- * stack). So we either find a way around these or just fault
- * and emulate if a guest tries to call swapgs directly.
- *
- * Either way, this is a good way to document that we don't
- * have a reliable stack. x86_64 only.
- */
-#define SWAPGS_UNSAFE_STACK swapgs
-
#define INTERRUPT_RETURN jmp native_iret
#define USERGS_SYSRET64 \
swapgs; \
@@ -170,6 +158,14 @@ static __always_inline int arch_irqs_disabled(void)
return arch_irqs_disabled_flags(flags);
}
+#else
+#ifdef CONFIG_X86_64
+#ifdef CONFIG_XEN_PV
+#define SWAPGS ALTERNATIVE "swapgs", "", X86_FEATURE_XENPV
+#else
+#define SWAPGS swapgs
+#endif
+#endif
#endif /* !__ASSEMBLY__ */
#endif
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index f8dce11d2bc1..f2ebe109a37e 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -776,26 +776,6 @@ extern void default_banner(void);
#ifdef CONFIG_X86_64
#ifdef CONFIG_PARAVIRT_XXL
-/*
- * If swapgs is used while the userspace stack is still current,
- * there's no way to call a pvop. The PV replacement *must* be
- * inlined, or the swapgs instruction must be trapped and emulated.
- */
-#define SWAPGS_UNSAFE_STACK \
- PARA_SITE(PARA_PATCH(PV_CPU_swapgs), swapgs)
-
-/*
- * Note: swapgs is very special, and in practise is either going to be
- * implemented with a single "swapgs" instruction or something very
- * special. Either way, we don't need to save any registers for
- * it.
- */
-#define SWAPGS \
- PARA_SITE(PARA_PATCH(PV_CPU_swapgs), \
- ANNOTATE_RETPOLINE_SAFE; \
- call PARA_INDIRECT(pv_ops+PV_CPU_swapgs); \
- )
-
#define USERGS_SYSRET64 \
PARA_SITE(PARA_PATCH(PV_CPU_usergs_sysret64), \
ANNOTATE_RETPOLINE_SAFE; \
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index b6b02b7c19cc..130f428b0cc8 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -168,8 +168,6 @@ struct pv_cpu_ops {
frame set up. */
void (*iret)(void);
- void (*swapgs)(void);
-
void (*start_context_switch)(struct task_struct *prev);
void (*end_context_switch)(struct task_struct *next);
#endif
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index 828be792231e..1354bc30614d 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -15,7 +15,6 @@ int main(void)
#ifdef CONFIG_PARAVIRT_XXL
OFFSET(PV_CPU_usergs_sysret64, paravirt_patch_template,
cpu.usergs_sysret64);
- OFFSET(PV_CPU_swapgs, paravirt_patch_template, cpu.swapgs);
#ifdef CONFIG_DEBUG_ENTRY
OFFSET(PV_IRQ_save_fl, paravirt_patch_template, irq.save_fl);
#endif
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 6c3407ba6ee9..5e5fcf5c376d 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -312,7 +312,6 @@ struct paravirt_patch_template pv_ops = {
.cpu.usergs_sysret64 = native_usergs_sysret64,
.cpu.iret = native_iret,
- .cpu.swapgs = native_swapgs,
#ifdef CONFIG_X86_IOPL_IOPERM
.cpu.invalidate_io_bitmap = native_tss_invalidate_io_bitmap,
diff --git a/arch/x86/kernel/paravirt_patch.c b/arch/x86/kernel/paravirt_patch.c
index ace6e334cb39..7c518b08aa3c 100644
--- a/arch/x86/kernel/paravirt_patch.c
+++ b/arch/x86/kernel/paravirt_patch.c
@@ -28,7 +28,6 @@ struct patch_xxl {
const unsigned char irq_restore_fl[2];
const unsigned char cpu_wbinvd[2];
const unsigned char cpu_usergs_sysret64[6];
- const unsigned char cpu_swapgs[3];
const unsigned char mov64[3];
};
@@ -43,7 +42,6 @@ static const struct patch_xxl patch_data_xxl = {
.cpu_wbinvd = { 0x0f, 0x09 }, // wbinvd
.cpu_usergs_sysret64 = { 0x0f, 0x01, 0xf8,
0x48, 0x0f, 0x07 }, // swapgs; sysretq
- .cpu_swapgs = { 0x0f, 0x01, 0xf8 }, // swapgs
.mov64 = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
};
@@ -86,7 +84,6 @@ unsigned int native_patch(u8 type, void *insn_buff, unsigned long addr,
PATCH_CASE(mmu, write_cr3, xxl, insn_buff, len);
PATCH_CASE(cpu, usergs_sysret64, xxl, insn_buff, len);
- PATCH_CASE(cpu, swapgs, xxl, insn_buff, len);
PATCH_CASE(cpu, wbinvd, xxl, insn_buff, len);
#endif
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 1fec2ee7a4dd..95f37996152a 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1098,9 +1098,6 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
#endif
.io_delay = xen_io_delay,
- /* Xen takes care of %gs when switching to usermode for us */
- .swapgs = paravirt_nop,
-
.start_context_switch = paravirt_start_context_switch,
.end_context_switch = xen_end_context_switch,
};
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-04 12:38:13 +0100