[PATCH v6 07/12] x86/paravirt: remove no longer needed 32-bit pvops cruft

From: Juergen Gross
Date: Tue Mar 09 2021 - 08:49:27 EST

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PVOP_VCALL4() is only used for Xen PV, while PVOP_CALL4() isn't used
at all. Keep PVOP_CALL4() for 64 bits due to symmetry reasons.

This allows to remove the 32-bit definitions of those macros leading
to a substantial simplification of the paravirt macros, as those were
the only ones needing non-empty "pre" and "post" parameters.

PVOP_CALLEE2() and PVOP_VCALLEE2() are used nowhere, so remove them.

Another no longer needed case is special handling of return types
larger than unsigned long. Replace that with a BUILD_BUG_ON().

DISABLE_INTERRUPTS() is used in 32-bit code only, so it can just be
replaced by cli.

INTERRUPT_RETURN in 32-bit code can be replaced by iret.

ENABLE_INTERRUPTS is used nowhere, so it can be removed.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/x86/entry/entry_32.S | 4 +-
arch/x86/include/asm/irqflags.h | 5 --
arch/x86/include/asm/paravirt.h | 35 +-------
arch/x86/include/asm/paravirt_types.h | 112 ++++++++------------------
arch/x86/kernel/asm-offsets.c | 2 -
5 files changed, 35 insertions(+), 123 deletions(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index df8c017e6161..765487e57d6e 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -430,7 +430,7 @@
* will soon execute iret and the tracer was already set to
* the irqstate after the IRET:
*/
- DISABLE_INTERRUPTS(CLBR_ANY)
+ cli
lss (%esp), %esp /* switch to espfix segment */
.Lend_\@:
#endif /* CONFIG_X86_ESPFIX32 */
@@ -1077,7 +1077,7 @@ restore_all_switch_stack:
* when returning from IPI handler and when returning from
* scheduler to user-space.
*/
- INTERRUPT_RETURN
+ iret

.section .fixup, "ax"
SYM_CODE_START(asm_iret_error)
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index 144d70ea4393..a0efbcd24b86 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -109,9 +109,6 @@ static __always_inline unsigned long arch_local_irq_save(void)
}
#else

-#define ENABLE_INTERRUPTS(x) sti
-#define DISABLE_INTERRUPTS(x) cli
-
#ifdef CONFIG_X86_64
#ifdef CONFIG_DEBUG_ENTRY
#define SAVE_FLAGS(x) pushfq; popq %rax
@@ -119,8 +116,6 @@ static __always_inline unsigned long arch_local_irq_save(void)

#define INTERRUPT_RETURN jmp native_iret

-#else
-#define INTERRUPT_RETURN iret
#endif

#endif /* __ASSEMBLY__ */
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 8c354099d9c3..c6496a82fad1 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -721,6 +721,7 @@ extern void default_banner(void);
.if ((~(set)) & mask); pop %reg; .endif

#ifdef CONFIG_X86_64
+#ifdef CONFIG_PARAVIRT_XXL

#define PV_SAVE_REGS(set) \
COND_PUSH(set, CLBR_RAX, rax); \
@@ -746,46 +747,12 @@ extern void default_banner(void);
#define PARA_PATCH(off) ((off) / 8)
#define PARA_SITE(ptype, ops) _PVSITE(ptype, ops, .quad, 8)
#define PARA_INDIRECT(addr) *addr(%rip)
-#else
-#define PV_SAVE_REGS(set) \
- COND_PUSH(set, CLBR_EAX, eax); \
- COND_PUSH(set, CLBR_EDI, edi); \
- COND_PUSH(set, CLBR_ECX, ecx); \
- COND_PUSH(set, CLBR_EDX, edx)
-#define PV_RESTORE_REGS(set) \
- COND_POP(set, CLBR_EDX, edx); \
- COND_POP(set, CLBR_ECX, ecx); \
- COND_POP(set, CLBR_EDI, edi); \
- COND_POP(set, CLBR_EAX, eax)
-
-#define PARA_PATCH(off) ((off) / 4)
-#define PARA_SITE(ptype, ops) _PVSITE(ptype, ops, .long, 4)
-#define PARA_INDIRECT(addr) *%cs:addr
-#endif

-#ifdef CONFIG_PARAVIRT_XXL
#define INTERRUPT_RETURN \
PARA_SITE(PARA_PATCH(PV_CPU_iret), \
ANNOTATE_RETPOLINE_SAFE; \
jmp PARA_INDIRECT(pv_ops+PV_CPU_iret);)

-#define DISABLE_INTERRUPTS(clobbers) \
- PARA_SITE(PARA_PATCH(PV_IRQ_irq_disable), \
- PV_SAVE_REGS(clobbers | CLBR_CALLEE_SAVE); \
- ANNOTATE_RETPOLINE_SAFE; \
- call PARA_INDIRECT(pv_ops+PV_IRQ_irq_disable); \
- PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
-
-#define ENABLE_INTERRUPTS(clobbers) \
- PARA_SITE(PARA_PATCH(PV_IRQ_irq_enable), \
- PV_SAVE_REGS(clobbers | CLBR_CALLEE_SAVE); \
- ANNOTATE_RETPOLINE_SAFE; \
- call PARA_INDIRECT(pv_ops+PV_IRQ_irq_enable); \
- PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
-#endif
-
-#ifdef CONFIG_X86_64
-#ifdef CONFIG_PARAVIRT_XXL
#ifdef CONFIG_DEBUG_ENTRY
#define SAVE_FLAGS(clobbers) \
PARA_SITE(PARA_PATCH(PV_IRQ_save_fl), \
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 1fff349e4792..42f9eef84131 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -470,55 +470,34 @@ int paravirt_disable_iospace(void);
})

-#define ____PVOP_CALL(rettype, op, clbr, call_clbr, extra_clbr, \
- pre, post, ...) \
+#define ____PVOP_CALL(rettype, op, clbr, call_clbr, extra_clbr, ...) \
({ \
- rettype __ret; \
PVOP_CALL_ARGS; \
PVOP_TEST_NULL(op); \
- /* This is 32-bit specific, but is okay in 64-bit */ \
- /* since this condition will never hold */ \
- if (sizeof(rettype) > sizeof(unsigned long)) { \
- asm volatile(pre \
- paravirt_alt(PARAVIRT_CALL) \
- post \
- : call_clbr, ASM_CALL_CONSTRAINT \
- : paravirt_type(op), \
- paravirt_clobber(clbr), \
- ##__VA_ARGS__ \
- : "memory", "cc" extra_clbr); \
- __ret = (rettype)((((u64)__edx) << 32) | __eax); \
- } else { \
- asm volatile(pre \
- paravirt_alt(PARAVIRT_CALL) \
- post \
- : call_clbr, ASM_CALL_CONSTRAINT \
- : paravirt_type(op), \
- paravirt_clobber(clbr), \
- ##__VA_ARGS__ \
- : "memory", "cc" extra_clbr); \
- __ret = (rettype)(__eax & PVOP_RETMASK(rettype)); \
- } \
- __ret; \
+ BUILD_BUG_ON(sizeof(rettype) > sizeof(unsigned long)); \
+ asm volatile(paravirt_alt(PARAVIRT_CALL) \
+ : call_clbr, ASM_CALL_CONSTRAINT \
+ : paravirt_type(op), \
+ paravirt_clobber(clbr), \
+ ##__VA_ARGS__ \
+ : "memory", "cc" extra_clbr); \
+ (rettype)(__eax & PVOP_RETMASK(rettype)); \
})

-#define __PVOP_CALL(rettype, op, pre, post, ...) \
+#define __PVOP_CALL(rettype, op, ...) \
____PVOP_CALL(rettype, op, CLBR_ANY, PVOP_CALL_CLOBBERS, \
- EXTRA_CLOBBERS, pre, post, ##__VA_ARGS__)
+ EXTRA_CLOBBERS, ##__VA_ARGS__)

-#define __PVOP_CALLEESAVE(rettype, op, pre, post, ...) \
+#define __PVOP_CALLEESAVE(rettype, op, ...) \
____PVOP_CALL(rettype, op.func, CLBR_RET_REG, \
- PVOP_CALLEE_CLOBBERS, , \
- pre, post, ##__VA_ARGS__)
+ PVOP_CALLEE_CLOBBERS, , ##__VA_ARGS__)

-#define ____PVOP_VCALL(op, clbr, call_clbr, extra_clbr, pre, post, ...) \
+#define ____PVOP_VCALL(op, clbr, call_clbr, extra_clbr, ...) \
({ \
PVOP_VCALL_ARGS; \
PVOP_TEST_NULL(op); \
- asm volatile(pre \
- paravirt_alt(PARAVIRT_CALL) \
- post \
+ asm volatile(paravirt_alt(PARAVIRT_CALL) \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
paravirt_clobber(clbr), \
@@ -526,84 +505,57 @@ int paravirt_disable_iospace(void);
: "memory", "cc" extra_clbr); \
})

-#define __PVOP_VCALL(op, pre, post, ...) \
+#define __PVOP_VCALL(op, ...) \
____PVOP_VCALL(op, CLBR_ANY, PVOP_VCALL_CLOBBERS, \
- VEXTRA_CLOBBERS, \
- pre, post, ##__VA_ARGS__)
+ VEXTRA_CLOBBERS, ##__VA_ARGS__)

-#define __PVOP_VCALLEESAVE(op, pre, post, ...) \
+#define __PVOP_VCALLEESAVE(op, ...) \
____PVOP_VCALL(op.func, CLBR_RET_REG, \
- PVOP_VCALLEE_CLOBBERS, , \
- pre, post, ##__VA_ARGS__)
+ PVOP_VCALLEE_CLOBBERS, , ##__VA_ARGS__)

#define PVOP_CALL0(rettype, op) \
- __PVOP_CALL(rettype, op, "", "")
+ __PVOP_CALL(rettype, op)
#define PVOP_VCALL0(op) \
- __PVOP_VCALL(op, "", "")
+ __PVOP_VCALL(op)

#define PVOP_CALLEE0(rettype, op) \
- __PVOP_CALLEESAVE(rettype, op, "", "")
+ __PVOP_CALLEESAVE(rettype, op)
#define PVOP_VCALLEE0(op) \
- __PVOP_VCALLEESAVE(op, "", "")
+ __PVOP_VCALLEESAVE(op)

#define PVOP_CALL1(rettype, op, arg1) \
- __PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1))
+ __PVOP_CALL(rettype, op, PVOP_CALL_ARG1(arg1))
#define PVOP_VCALL1(op, arg1) \
- __PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1))
+ __PVOP_VCALL(op, PVOP_CALL_ARG1(arg1))

#define PVOP_CALLEE1(rettype, op, arg1) \
- __PVOP_CALLEESAVE(rettype, op, "", "", PVOP_CALL_ARG1(arg1))
+ __PVOP_CALLEESAVE(rettype, op, PVOP_CALL_ARG1(arg1))
#define PVOP_VCALLEE1(op, arg1) \
- __PVOP_VCALLEESAVE(op, "", "", PVOP_CALL_ARG1(arg1))
+ __PVOP_VCALLEESAVE(op, PVOP_CALL_ARG1(arg1))

#define PVOP_CALL2(rettype, op, arg1, arg2) \
- __PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
- PVOP_CALL_ARG2(arg2))
+ __PVOP_CALL(rettype, op, PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2))
#define PVOP_VCALL2(op, arg1, arg2) \
- __PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1), \
- PVOP_CALL_ARG2(arg2))
-
-#define PVOP_CALLEE2(rettype, op, arg1, arg2) \
- __PVOP_CALLEESAVE(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
- PVOP_CALL_ARG2(arg2))
-#define PVOP_VCALLEE2(op, arg1, arg2) \
- __PVOP_VCALLEESAVE(op, "", "", PVOP_CALL_ARG1(arg1), \
- PVOP_CALL_ARG2(arg2))
-
+ __PVOP_VCALL(op, PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2))

#define PVOP_CALL3(rettype, op, arg1, arg2, arg3) \
- __PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
+ __PVOP_CALL(rettype, op, PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2), PVOP_CALL_ARG3(arg3))
#define PVOP_VCALL3(op, arg1, arg2, arg3) \
- __PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1), \
+ __PVOP_VCALL(op, PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2), PVOP_CALL_ARG3(arg3))

-/* This is the only difference in x86_64. We can make it much simpler */
-#ifdef CONFIG_X86_32
#define PVOP_CALL4(rettype, op, arg1, arg2, arg3, arg4) \
__PVOP_CALL(rettype, op, \
- "push %[_arg4];", "lea 4(%%esp),%%esp;", \
- PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
- PVOP_CALL_ARG3(arg3), [_arg4] "mr" ((u32)(arg4)))
-#define PVOP_VCALL4(op, arg1, arg2, arg3, arg4) \
- __PVOP_VCALL(op, \
- "push %[_arg4];", "lea 4(%%esp),%%esp;", \
- "0" ((u32)(arg1)), "1" ((u32)(arg2)), \
- "2" ((u32)(arg3)), [_arg4] "mr" ((u32)(arg4)))
-#else
-#define PVOP_CALL4(rettype, op, arg1, arg2, arg3, arg4) \
- __PVOP_CALL(rettype, op, "", "", \
PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4))
#define PVOP_VCALL4(op, arg1, arg2, arg3, arg4) \
- __PVOP_VCALL(op, "", "", \
- PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
+ __PVOP_VCALL(op, PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4))
-#endif

/* Lazy mode for batching updates / context switch */
enum paravirt_lazy_mode {
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 60b9f42ce3c1..736508004b30 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -63,8 +63,6 @@ static void __used common(void)

#ifdef CONFIG_PARAVIRT_XXL
BLANK();
- OFFSET(PV_IRQ_irq_disable, paravirt_patch_template, irq.irq_disable);
- OFFSET(PV_IRQ_irq_enable, paravirt_patch_template, irq.irq_enable);
OFFSET(PV_CPU_iret, paravirt_patch_template, cpu.iret);
#endif

--
2.26.2

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