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x86/paravirt: use callee-saved convention for pte_val/make_pte/etc
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Impact: Optimization

In the native case, pte_val, make_pte, etc are all just identity
functions, so there's no need to clobber a lot of registers over them.

(This changes the 32-bit callee-save calling convention to return both
EAX and EDX so functions can return 64-bit values.)

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Jeremy Fitzhardinge authored and H. Peter Anvin committed Jan 30, 2009
1 parent 791bad9 commit da5de7c
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Showing 3 changed files with 67 additions and 88 deletions.
78 changes: 39 additions & 39 deletions arch/x86/include/asm/paravirt.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@
#define CLBR_ANY ((1 << 4) - 1)

#define CLBR_ARG_REGS (CLBR_EAX | CLBR_EDX | CLBR_ECX)
#define CLBR_RET_REG (CLBR_EAX)
#define CLBR_RET_REG (CLBR_EAX | CLBR_EDX)
#define CLBR_SCRATCH (0)
#else
#define CLBR_RAX CLBR_EAX
Expand Down Expand Up @@ -308,11 +308,11 @@ struct pv_mmu_ops {
void (*ptep_modify_prot_commit)(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte);

pteval_t (*pte_val)(pte_t);
pte_t (*make_pte)(pteval_t pte);
struct paravirt_callee_save pte_val;
struct paravirt_callee_save make_pte;

pgdval_t (*pgd_val)(pgd_t);
pgd_t (*make_pgd)(pgdval_t pgd);
struct paravirt_callee_save pgd_val;
struct paravirt_callee_save make_pgd;

#if PAGETABLE_LEVELS >= 3
#ifdef CONFIG_X86_PAE
Expand All @@ -327,12 +327,12 @@ struct pv_mmu_ops {

void (*set_pud)(pud_t *pudp, pud_t pudval);

pmdval_t (*pmd_val)(pmd_t);
pmd_t (*make_pmd)(pmdval_t pmd);
struct paravirt_callee_save pmd_val;
struct paravirt_callee_save make_pmd;

#if PAGETABLE_LEVELS == 4
pudval_t (*pud_val)(pud_t);
pud_t (*make_pud)(pudval_t pud);
struct paravirt_callee_save pud_val;
struct paravirt_callee_save make_pud;

void (*set_pgd)(pgd_t *pudp, pgd_t pgdval);
#endif /* PAGETABLE_LEVELS == 4 */
Expand Down Expand Up @@ -1155,13 +1155,13 @@ static inline pte_t __pte(pteval_t val)
pteval_t ret;

if (sizeof(pteval_t) > sizeof(long))
ret = PVOP_CALL2(pteval_t,
pv_mmu_ops.make_pte,
val, (u64)val >> 32);
ret = PVOP_CALLEE2(pteval_t,
pv_mmu_ops.make_pte,
val, (u64)val >> 32);
else
ret = PVOP_CALL1(pteval_t,
pv_mmu_ops.make_pte,
val);
ret = PVOP_CALLEE1(pteval_t,
pv_mmu_ops.make_pte,
val);

return (pte_t) { .pte = ret };
}
Expand All @@ -1171,11 +1171,11 @@ static inline pteval_t pte_val(pte_t pte)
pteval_t ret;

if (sizeof(pteval_t) > sizeof(long))
ret = PVOP_CALL2(pteval_t, pv_mmu_ops.pte_val,
pte.pte, (u64)pte.pte >> 32);
ret = PVOP_CALLEE2(pteval_t, pv_mmu_ops.pte_val,
pte.pte, (u64)pte.pte >> 32);
else
ret = PVOP_CALL1(pteval_t, pv_mmu_ops.pte_val,
pte.pte);
ret = PVOP_CALLEE1(pteval_t, pv_mmu_ops.pte_val,
pte.pte);

return ret;
}
Expand All @@ -1185,11 +1185,11 @@ static inline pgd_t __pgd(pgdval_t val)
pgdval_t ret;

if (sizeof(pgdval_t) > sizeof(long))
ret = PVOP_CALL2(pgdval_t, pv_mmu_ops.make_pgd,
val, (u64)val >> 32);
ret = PVOP_CALLEE2(pgdval_t, pv_mmu_ops.make_pgd,
val, (u64)val >> 32);
else
ret = PVOP_CALL1(pgdval_t, pv_mmu_ops.make_pgd,
val);
ret = PVOP_CALLEE1(pgdval_t, pv_mmu_ops.make_pgd,
val);

return (pgd_t) { ret };
}
Expand All @@ -1199,11 +1199,11 @@ static inline pgdval_t pgd_val(pgd_t pgd)
pgdval_t ret;

if (sizeof(pgdval_t) > sizeof(long))
ret = PVOP_CALL2(pgdval_t, pv_mmu_ops.pgd_val,
pgd.pgd, (u64)pgd.pgd >> 32);
ret = PVOP_CALLEE2(pgdval_t, pv_mmu_ops.pgd_val,
pgd.pgd, (u64)pgd.pgd >> 32);
else
ret = PVOP_CALL1(pgdval_t, pv_mmu_ops.pgd_val,
pgd.pgd);
ret = PVOP_CALLEE1(pgdval_t, pv_mmu_ops.pgd_val,
pgd.pgd);

return ret;
}
Expand Down Expand Up @@ -1267,11 +1267,11 @@ static inline pmd_t __pmd(pmdval_t val)
pmdval_t ret;

if (sizeof(pmdval_t) > sizeof(long))
ret = PVOP_CALL2(pmdval_t, pv_mmu_ops.make_pmd,
val, (u64)val >> 32);
ret = PVOP_CALLEE2(pmdval_t, pv_mmu_ops.make_pmd,
val, (u64)val >> 32);
else
ret = PVOP_CALL1(pmdval_t, pv_mmu_ops.make_pmd,
val);
ret = PVOP_CALLEE1(pmdval_t, pv_mmu_ops.make_pmd,
val);

return (pmd_t) { ret };
}
Expand All @@ -1281,11 +1281,11 @@ static inline pmdval_t pmd_val(pmd_t pmd)
pmdval_t ret;

if (sizeof(pmdval_t) > sizeof(long))
ret = PVOP_CALL2(pmdval_t, pv_mmu_ops.pmd_val,
pmd.pmd, (u64)pmd.pmd >> 32);
ret = PVOP_CALLEE2(pmdval_t, pv_mmu_ops.pmd_val,
pmd.pmd, (u64)pmd.pmd >> 32);
else
ret = PVOP_CALL1(pmdval_t, pv_mmu_ops.pmd_val,
pmd.pmd);
ret = PVOP_CALLEE1(pmdval_t, pv_mmu_ops.pmd_val,
pmd.pmd);

return ret;
}
Expand All @@ -1307,11 +1307,11 @@ static inline pud_t __pud(pudval_t val)
pudval_t ret;

if (sizeof(pudval_t) > sizeof(long))
ret = PVOP_CALL2(pudval_t, pv_mmu_ops.make_pud,
val, (u64)val >> 32);
ret = PVOP_CALLEE2(pudval_t, pv_mmu_ops.make_pud,
val, (u64)val >> 32);
else
ret = PVOP_CALL1(pudval_t, pv_mmu_ops.make_pud,
val);
ret = PVOP_CALLEE1(pudval_t, pv_mmu_ops.make_pud,
val);

return (pud_t) { ret };
}
Expand Down
53 changes: 12 additions & 41 deletions arch/x86/kernel/paravirt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -391,43 +391,12 @@ struct pv_apic_ops pv_apic_ops = {
#endif
};

typedef pte_t make_pte_t(pteval_t);
typedef pmd_t make_pmd_t(pmdval_t);
typedef pud_t make_pud_t(pudval_t);
typedef pgd_t make_pgd_t(pgdval_t);

typedef pteval_t pte_val_t(pte_t);
typedef pmdval_t pmd_val_t(pmd_t);
typedef pudval_t pud_val_t(pud_t);
typedef pgdval_t pgd_val_t(pgd_t);


#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
/* 32-bit pagetable entries */
#define paravirt_native_make_pte (make_pte_t *)_paravirt_ident_32
#define paravirt_native_pte_val (pte_val_t *)_paravirt_ident_32

#define paravirt_native_make_pmd (make_pmd_t *)_paravirt_ident_32
#define paravirt_native_pmd_val (pmd_val_t *)_paravirt_ident_32

#define paravirt_native_make_pud (make_pud_t *)_paravirt_ident_32
#define paravirt_native_pud_val (pud_val_t *)_paravirt_ident_32

#define paravirt_native_make_pgd (make_pgd_t *)_paravirt_ident_32
#define paravirt_native_pgd_val (pgd_val_t *)_paravirt_ident_32
#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_32)
#else
/* 64-bit pagetable entries */
#define paravirt_native_make_pte (make_pte_t *)_paravirt_ident_64
#define paravirt_native_pte_val (pte_val_t *)_paravirt_ident_64

#define paravirt_native_make_pmd (make_pmd_t *)_paravirt_ident_64
#define paravirt_native_pmd_val (pmd_val_t *)_paravirt_ident_64

#define paravirt_native_make_pud (make_pud_t *)_paravirt_ident_64
#define paravirt_native_pud_val (pud_val_t *)_paravirt_ident_64

#define paravirt_native_make_pgd (make_pgd_t *)_paravirt_ident_64
#define paravirt_native_pgd_val (pgd_val_t *)_paravirt_ident_64
#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
#endif

struct pv_mmu_ops pv_mmu_ops = {
Expand Down Expand Up @@ -481,21 +450,23 @@ struct pv_mmu_ops pv_mmu_ops = {
.pmd_clear = native_pmd_clear,
#endif
.set_pud = native_set_pud,
.pmd_val = paravirt_native_pmd_val,
.make_pmd = paravirt_native_make_pmd,

.pmd_val = PTE_IDENT,
.make_pmd = PTE_IDENT,

#if PAGETABLE_LEVELS == 4
.pud_val = paravirt_native_pud_val,
.make_pud = paravirt_native_make_pud,
.pud_val = PTE_IDENT,
.make_pud = PTE_IDENT,

.set_pgd = native_set_pgd,
#endif
#endif /* PAGETABLE_LEVELS >= 3 */

.pte_val = paravirt_native_pte_val,
.pgd_val = paravirt_native_pgd_val,
.pte_val = PTE_IDENT,
.pgd_val = PTE_IDENT,

.make_pte = paravirt_native_make_pte,
.make_pgd = paravirt_native_make_pgd,
.make_pte = PTE_IDENT,
.make_pgd = PTE_IDENT,

.dup_mmap = paravirt_nop,
.exit_mmap = paravirt_nop,
Expand Down
24 changes: 16 additions & 8 deletions arch/x86/xen/mmu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -492,28 +492,33 @@ pteval_t xen_pte_val(pte_t pte)
{
return pte_mfn_to_pfn(pte.pte);
}
PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);

pgdval_t xen_pgd_val(pgd_t pgd)
{
return pte_mfn_to_pfn(pgd.pgd);
}
PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);

pte_t xen_make_pte(pteval_t pte)
{
pte = pte_pfn_to_mfn(pte);
return native_make_pte(pte);
}
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);

pgd_t xen_make_pgd(pgdval_t pgd)
{
pgd = pte_pfn_to_mfn(pgd);
return native_make_pgd(pgd);
}
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);

pmdval_t xen_pmd_val(pmd_t pmd)
{
return pte_mfn_to_pfn(pmd.pmd);
}
PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);

void xen_set_pud_hyper(pud_t *ptr, pud_t val)
{
Expand Down Expand Up @@ -590,19 +595,22 @@ pmd_t xen_make_pmd(pmdval_t pmd)
pmd = pte_pfn_to_mfn(pmd);
return native_make_pmd(pmd);
}
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);

#if PAGETABLE_LEVELS == 4
pudval_t xen_pud_val(pud_t pud)
{
return pte_mfn_to_pfn(pud.pud);
}
PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);

pud_t xen_make_pud(pudval_t pud)
{
pud = pte_pfn_to_mfn(pud);

return native_make_pud(pud);
}
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);

pgd_t *xen_get_user_pgd(pgd_t *pgd)
{
Expand Down Expand Up @@ -1813,11 +1821,11 @@ const struct pv_mmu_ops xen_mmu_ops __initdata = {
.ptep_modify_prot_start = __ptep_modify_prot_start,
.ptep_modify_prot_commit = __ptep_modify_prot_commit,

.pte_val = xen_pte_val,
.pgd_val = xen_pgd_val,
.pte_val = PV_CALLEE_SAVE(xen_pte_val),
.pgd_val = PV_CALLEE_SAVE(xen_pgd_val),

.make_pte = xen_make_pte,
.make_pgd = xen_make_pgd,
.make_pte = PV_CALLEE_SAVE(xen_make_pte),
.make_pgd = PV_CALLEE_SAVE(xen_make_pgd),

#ifdef CONFIG_X86_PAE
.set_pte_atomic = xen_set_pte_atomic,
Expand All @@ -1827,12 +1835,12 @@ const struct pv_mmu_ops xen_mmu_ops __initdata = {
#endif /* CONFIG_X86_PAE */
.set_pud = xen_set_pud_hyper,

.make_pmd = xen_make_pmd,
.pmd_val = xen_pmd_val,
.make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
.pmd_val = PV_CALLEE_SAVE(xen_pmd_val),

#if PAGETABLE_LEVELS == 4
.pud_val = xen_pud_val,
.make_pud = xen_make_pud,
.pud_val = PV_CALLEE_SAVE(xen_pud_val),
.make_pud = PV_CALLEE_SAVE(xen_make_pud),
.set_pgd = xen_set_pgd_hyper,

.alloc_pud = xen_alloc_pte_init,
Expand Down

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