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- Convert a couple of paravirt callbacks to asm to prevent 

-fzero-call-used-regs builds from zeroing live registers because
   paravirt hides the CALLs from the compiler so latter doesn't know
   there's a CALL in the first place
 
 - Merge two paravirt callbacks into one, as their functionality is
   identical
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Merge tag 'x86_paravirt_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 paravirt updates from Borislav Petkov:

 - Convert a couple of paravirt callbacks to asm to prevent
   '-fzero-call-used-regs' builds from zeroing live registers because
   paravirt hides the CALLs from the compiler so latter doesn't know
   there's a CALL in the first place

 - Merge two paravirt callbacks into one, as their functionality is
   identical

* tag 'x86_paravirt_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/paravirt: Convert simple paravirt functions to asm
  x86/paravirt: Merge activate_mm() and dup_mmap() callbacks
This commit is contained in:
Linus Torvalds 2023-04-25 10:32:51 -07:00
parent 4a4a28fca6 11af36cb89
commit c42b59bfaa
6 changed files with 24 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
arch/x86/include/asm/mmu_context.h
View File

@ -16,13 +16,6 @@
extern atomic64_t last_mm_ctx_id;
#ifndef CONFIG_PARAVIRT_XXL
static inline void paravirt_activate_mm(struct mm_struct *prev,
struct mm_struct *next)
{
}
#endif /* !CONFIG_PARAVIRT_XXL */
#ifdef CONFIG_PERF_EVENTS
DECLARE_STATIC_KEY_FALSE(rdpmc_never_available_key);
DECLARE_STATIC_KEY_FALSE(rdpmc_always_available_key);
@ -135,7 +128,7 @@ extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
#define activate_mm(prev, next) \
do { \
paravirt_activate_mm((prev), (next)); \
paravirt_enter_mmap(next); \
switch_mm((prev), (next), NULL); \
} while (0);
@ -168,7 +161,7 @@ static inline void arch_dup_pkeys(struct mm_struct *oldmm,
static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
{
arch_dup_pkeys(oldmm, mm);
paravirt_arch_dup_mmap(oldmm, mm);
paravirt_enter_mmap(mm);
return ldt_dup_context(oldmm, mm);
}

14
arch/x86/include/asm/paravirt.h
View File

@ -334,16 +334,9 @@ static inline void tss_update_io_bitmap(void)
}
#endif
static inline void paravirt_activate_mm(struct mm_struct *prev,
struct mm_struct *next)
static inline void paravirt_enter_mmap(struct mm_struct *next)
{
PVOP_VCALL2(mmu.activate_mm, prev, next);
}
static inline void paravirt_arch_dup_mmap(struct mm_struct *oldmm,
struct mm_struct *mm)
{
PVOP_VCALL2(mmu.dup_mmap, oldmm, mm);
PVOP_VCALL1(mmu.enter_mmap, next);
}
static inline int paravirt_pgd_alloc(struct mm_struct *mm)
@ -789,8 +782,7 @@ extern void default_banner(void);
#ifndef __ASSEMBLY__
#ifndef CONFIG_PARAVIRT_XXL
static inline void paravirt_arch_dup_mmap(struct mm_struct *oldmm,
struct mm_struct *mm)
static inline void paravirt_enter_mmap(struct mm_struct *mm)
{
}
#endif

15
arch/x86/include/asm/paravirt_types.h
View File

@ -164,11 +164,8 @@ struct pv_mmu_ops {
unsigned long (*read_cr3)(void);
void (*write_cr3)(unsigned long);
/* Hooks for intercepting the creation/use of an mm_struct. */
void (*activate_mm)(struct mm_struct *prev,
struct mm_struct *next);
void (*dup_mmap)(struct mm_struct *oldmm,
struct mm_struct *mm);
/* Hook for intercepting the creation/use of an mm_struct. */
void (*enter_mmap)(struct mm_struct *mm);
/* Hooks for allocating and freeing a pagetable top-level */
int (*pgd_alloc)(struct mm_struct *mm);
@ -562,8 +559,14 @@ void paravirt_flush_lazy_mmu(void);
void _paravirt_nop(void);
void paravirt_BUG(void);
u64 _paravirt_ident_64(u64);
unsigned long paravirt_ret0(void);
#ifdef CONFIG_PARAVIRT_XXL
u64 _paravirt_ident_64(u64);
unsigned long pv_native_save_fl(void);
void pv_native_irq_disable(void);
void pv_native_irq_enable(void);
unsigned long pv_native_read_cr2(void);
#endif
#define paravirt_nop ((void *)_paravirt_nop)

30
arch/x86/kernel/paravirt.c
View File

@ -64,11 +64,11 @@ static unsigned paravirt_patch_call(void *insn_buff, const void *target,
}
#ifdef CONFIG_PARAVIRT_XXL
/* identity function, which can be inlined */
u64 notrace _paravirt_ident_64(u64 x)
{
return x;
}
DEFINE_PARAVIRT_ASM(_paravirt_ident_64, "mov %rdi, %rax", .text);
DEFINE_PARAVIRT_ASM(pv_native_save_fl, "pushf; pop %rax", .noinstr.text);
DEFINE_PARAVIRT_ASM(pv_native_irq_disable, "cli", .noinstr.text);
DEFINE_PARAVIRT_ASM(pv_native_irq_enable, "sti", .noinstr.text);
DEFINE_PARAVIRT_ASM(pv_native_read_cr2, "mov %cr2, %rax", .noinstr.text);
#endif
DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key);
@ -197,11 +197,6 @@ void paravirt_end_context_switch(struct task_struct *next)
arch_enter_lazy_mmu_mode();
}
static noinstr unsigned long pv_native_read_cr2(void)
{
return native_read_cr2();
}
static noinstr void pv_native_write_cr2(unsigned long val)
{
native_write_cr2(val);
@ -222,16 +217,6 @@ noinstr void pv_native_wbinvd(void)
native_wbinvd();
}
static noinstr void pv_native_irq_enable(void)
{
native_irq_enable();
}
static noinstr void pv_native_irq_disable(void)
{
native_irq_disable();
}
static noinstr void pv_native_safe_halt(void)
{
native_safe_halt();
@ -298,7 +283,7 @@ struct paravirt_patch_template pv_ops = {
.cpu.end_context_switch = paravirt_nop,
/* Irq ops. */
.irq.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
.irq.save_fl = __PV_IS_CALLEE_SAVE(pv_native_save_fl),
.irq.irq_disable = __PV_IS_CALLEE_SAVE(pv_native_irq_disable),
.irq.irq_enable = __PV_IS_CALLEE_SAVE(pv_native_irq_enable),
.irq.safe_halt = pv_native_safe_halt,
@ -363,8 +348,7 @@ struct paravirt_patch_template pv_ops = {
.mmu.make_pte = PTE_IDENT,
.mmu.make_pgd = PTE_IDENT,
.mmu.dup_mmap = paravirt_nop,
.mmu.activate_mm = paravirt_nop,
.mmu.enter_mmap = paravirt_nop,
.mmu.lazy_mode = {
.enter = paravirt_nop,

2
arch/x86/mm/init.c
View File

@ -806,7 +806,7 @@ void __init poking_init(void)
BUG_ON(!poking_mm);
/* Xen PV guests need the PGD to be pinned. */
paravirt_arch_dup_mmap(NULL, poking_mm);
paravirt_enter_mmap(poking_mm);
/*
* Randomize the poking address, but make sure that the following page

12
arch/x86/xen/mmu_pv.c
View File

@ -885,14 +885,7 @@ void xen_mm_unpin_all(void)
spin_unlock(&pgd_lock);
}
static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
spin_lock(&next->page_table_lock);
xen_pgd_pin(next);
spin_unlock(&next->page_table_lock);
}
static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
static void xen_enter_mmap(struct mm_struct *mm)
{
spin_lock(&mm->page_table_lock);
xen_pgd_pin(mm);
@ -2153,8 +2146,7 @@ static const typeof(pv_ops) xen_mmu_ops __initconst = {
.make_p4d = PV_CALLEE_SAVE(xen_make_p4d),
#endif
.activate_mm = xen_activate_mm,
.dup_mmap = xen_dup_mmap,
.enter_mmap = xen_enter_mmap,
.exit_mmap = xen_exit_mmap,
.lazy_mode = {