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Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse Source 
Pull x86 fixes from Ingo Molnar:
 "Another round of CR3/PCID related fixes (I think this addresses all
  but one of the known problems with PCID support), an objtool fix plus
  a Clang fix that (finally) solves all Clang quirks to build a bootable
  x86 kernel as-is"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/asm: Fix inline asm call constraints for Clang
  objtool: Handle another GCC stack pointer adjustment bug
  x86/mm/32: Load a sane CR3 before cpu_init() on secondary CPUs
  x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier
  x86/mm/64: Stop using CR3.PCID == 0 in ASID-aware code
  x86/mm: Factor out CR3-building code
This commit is contained in:
Linus Torvalds 2017-09-24 12:33:58 -07:00
commit a141fd55f2
20 changed files with 122 additions and 86 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/include/asm/alternative.h
View File

@ -218,10 +218,9 @@ static inline int alternatives_text_reserved(void *start, void *end)
#define alternative_call_2(oldfunc, newfunc1, feature1, newfunc2, feature2, \
output, input...) \
{ \
register void *__sp asm(_ASM_SP); \
asm volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\
"call %P[new2]", feature2) \
: output, "+r" (__sp) \
: output, ASM_CALL_CONSTRAINT \
: [old] "i" (oldfunc), [new1] "i" (newfunc1), \
[new2] "i" (newfunc2), ## input); \
}

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

@ -132,4 +132,15 @@
/* For C file, we already have NOKPROBE_SYMBOL macro */
#endif
#ifndef __ASSEMBLY__
/*
* This output constraint should be used for any inline asm which has a "call"
* instruction. Otherwise the asm may be inserted before the frame pointer
* gets set up by the containing function. If you forget to do this, objtool
* may print a "call without frame pointer save/setup" warning.
*/
register unsigned int __asm_call_sp asm("esp");
#define ASM_CALL_CONSTRAINT "+r" (__asm_call_sp)
#endif
#endif /* _ASM_X86_ASM_H */

32
arch/x86/include/asm/mmu_context.h
View File

@ -286,6 +286,32 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
return __pkru_allows_pkey(vma_pkey(vma), write);
}
/*
* If PCID is on, ASID-aware code paths put the ASID+1 into the PCID
* bits. This serves two purposes. It prevents a nasty situation in
* which PCID-unaware code saves CR3, loads some other value (with PCID
* == 0), and then restores CR3, thus corrupting the TLB for ASID 0 if
* the saved ASID was nonzero. It also means that any bugs involving
* loading a PCID-enabled CR3 with CR4.PCIDE off will trigger
* deterministically.
*/
static inline unsigned long build_cr3(struct mm_struct *mm, u16 asid)
{
if (static_cpu_has(X86_FEATURE_PCID)) {
VM_WARN_ON_ONCE(asid > 4094);
return __sme_pa(mm->pgd) | (asid + 1);
} else {
VM_WARN_ON_ONCE(asid != 0);
return __sme_pa(mm->pgd);
}
}
static inline unsigned long build_cr3_noflush(struct mm_struct *mm, u16 asid)
{
VM_WARN_ON_ONCE(asid > 4094);
return __sme_pa(mm->pgd) | (asid + 1) | CR3_NOFLUSH;
}
/*
* This can be used from process context to figure out what the value of
@ -296,10 +322,8 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
*/
static inline unsigned long __get_current_cr3_fast(void)
{
unsigned long cr3 = __pa(this_cpu_read(cpu_tlbstate.loaded_mm)->pgd);
if (static_cpu_has(X86_FEATURE_PCID))
cr3 |= this_cpu_read(cpu_tlbstate.loaded_mm_asid);
unsigned long cr3 = build_cr3(this_cpu_read(cpu_tlbstate.loaded_mm),
this_cpu_read(cpu_tlbstate.loaded_mm_asid));
/* For now, be very restrictive about when this can be called. */
VM_WARN_ON(in_nmi() || preemptible());

10
arch/x86/include/asm/mshyperv.h
View File

@ -179,7 +179,6 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
u64 input_address = input ? virt_to_phys(input) : 0;
u64 output_address = output ? virt_to_phys(output) : 0;
u64 hv_status;
register void *__sp asm(_ASM_SP);
#ifdef CONFIG_X86_64
if (!hv_hypercall_pg)
@ -187,7 +186,7 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
__asm__ __volatile__("mov %4, %%r8\n"
"call *%5"
: "=a" (hv_status), "+r" (__sp),
: "=a" (hv_status), ASM_CALL_CONSTRAINT,
"+c" (control), "+d" (input_address)
: "r" (output_address), "m" (hv_hypercall_pg)
: "cc", "memory", "r8", "r9", "r10", "r11");
@ -202,7 +201,7 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
__asm__ __volatile__("call *%7"
: "=A" (hv_status),
"+c" (input_address_lo), "+r" (__sp)
"+c" (input_address_lo), ASM_CALL_CONSTRAINT
: "A" (control),
"b" (input_address_hi),
"D"(output_address_hi), "S"(output_address_lo),
@ -224,12 +223,11 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
{
u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
register void *__sp asm(_ASM_SP);
#ifdef CONFIG_X86_64
{
__asm__ __volatile__("call *%4"
: "=a" (hv_status), "+r" (__sp),
: "=a" (hv_status), ASM_CALL_CONSTRAINT,
"+c" (control), "+d" (input1)
: "m" (hv_hypercall_pg)
: "cc", "r8", "r9", "r10", "r11");
@ -242,7 +240,7 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
__asm__ __volatile__ ("call *%5"
: "=A"(hv_status),
"+c"(input1_lo),
"+r"(__sp)
ASM_CALL_CONSTRAINT
: "A" (control),
"b" (input1_hi),
"m" (hv_hypercall_pg)

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

@ -459,8 +459,8 @@ int paravirt_disable_iospace(void);
*/
#ifdef CONFIG_X86_32
#define PVOP_VCALL_ARGS \
unsigned long __eax = __eax, __edx = __edx, __ecx = __ecx; \
register void *__sp asm("esp")
unsigned long __eax = __eax, __edx = __edx, __ecx = __ecx;
#define PVOP_CALL_ARGS PVOP_VCALL_ARGS
#define PVOP_CALL_ARG1(x) "a" ((unsigned long)(x))
@ -480,8 +480,8 @@ int paravirt_disable_iospace(void);
/* [re]ax isn't an arg, but the return val */
#define PVOP_VCALL_ARGS \
unsigned long __edi = __edi, __esi = __esi, \
__edx = __edx, __ecx = __ecx, __eax = __eax; \
register void *__sp asm("rsp")
__edx = __edx, __ecx = __ecx, __eax = __eax;
#define PVOP_CALL_ARGS PVOP_VCALL_ARGS
#define PVOP_CALL_ARG1(x) "D" ((unsigned long)(x))
@ -532,7 +532,7 @@ int paravirt_disable_iospace(void);
asm volatile(pre \
paravirt_alt(PARAVIRT_CALL) \
post \
: call_clbr, "+r" (__sp) \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
paravirt_clobber(clbr), \
##__VA_ARGS__ \
@ -542,7 +542,7 @@ int paravirt_disable_iospace(void);
asm volatile(pre \
paravirt_alt(PARAVIRT_CALL) \
post \
: call_clbr, "+r" (__sp) \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
paravirt_clobber(clbr), \
##__VA_ARGS__ \
@ -569,7 +569,7 @@ int paravirt_disable_iospace(void);
asm volatile(pre \
paravirt_alt(PARAVIRT_CALL) \
post \
: call_clbr, "+r" (__sp) \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
paravirt_clobber(clbr), \
##__VA_ARGS__ \

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

@ -100,19 +100,14 @@ static __always_inline bool should_resched(int preempt_offset)
#ifdef CONFIG_PREEMPT
extern asmlinkage void ___preempt_schedule(void);
# define __preempt_schedule() \
({ \
register void *__sp asm(_ASM_SP); \
asm volatile ("call ___preempt_schedule" : "+r"(__sp)); \
})
# define __preempt_schedule() \
asm volatile ("call ___preempt_schedule" : ASM_CALL_CONSTRAINT)
extern asmlinkage void preempt_schedule(void);
extern asmlinkage void ___preempt_schedule_notrace(void);
# define __preempt_schedule_notrace() \
({ \
register void *__sp asm(_ASM_SP); \
asm volatile ("call ___preempt_schedule_notrace" : "+r"(__sp)); \
})
# define __preempt_schedule_notrace() \
asm volatile ("call ___preempt_schedule_notrace" : ASM_CALL_CONSTRAINT)
extern asmlinkage void preempt_schedule_notrace(void);
#endif

6
arch/x86/include/asm/processor.h
View File

@ -677,8 +677,6 @@ static inline void sync_core(void)
* Like all of Linux's memory ordering operations, this is a
* compiler barrier as well.
*/
register void *__sp asm(_ASM_SP);
#ifdef CONFIG_X86_32
asm volatile (
"pushfl\n\t"
@ -686,7 +684,7 @@ static inline void sync_core(void)
"pushl $1f\n\t"
"iret\n\t"
"1:"
: "+r" (__sp) : : "memory");
: ASM_CALL_CONSTRAINT : : "memory");
#else
unsigned int tmp;
@ -703,7 +701,7 @@ static inline void sync_core(void)
"iretq\n\t"
UNWIND_HINT_RESTORE
"1:"
: "=&r" (tmp), "+r" (__sp) : : "cc", "memory");
: "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
#endif
}

4
arch/x86/include/asm/rwsem.h
View File

@ -103,7 +103,6 @@ static inline bool __down_read_trylock(struct rw_semaphore *sem)
({ \
long tmp; \
struct rw_semaphore* ret; \
register void *__sp asm(_ASM_SP); \
\
asm volatile("# beginning down_write\n\t" \
LOCK_PREFIX " xadd %1,(%4)\n\t" \
@ -114,7 +113,8 @@ static inline bool __down_read_trylock(struct rw_semaphore *sem)
" call " slow_path "\n" \
"1:\n" \
"# ending down_write" \
: "+m" (sem->count), "=d" (tmp), "=a" (ret), "+r" (__sp) \
: "+m" (sem->count), "=d" (tmp), \
"=a" (ret), ASM_CALL_CONSTRAINT \
: "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) \
: "memory", "cc"); \
ret; \

4
arch/x86/include/asm/uaccess.h
View File

@ -166,11 +166,11 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
({ \
int __ret_gu; \
register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \
register void *__sp asm(_ASM_SP); \
__chk_user_ptr(ptr); \
might_fault(); \
asm volatile("call __get_user_%P4" \
: "=a" (__ret_gu), "=r" (__val_gu), "+r" (__sp) \
: "=a" (__ret_gu), "=r" (__val_gu), \
ASM_CALL_CONSTRAINT \
: "0" (ptr), "i" (sizeof(*(ptr)))); \
(x) = (__force __typeof__(*(ptr))) __val_gu; \
__builtin_expect(__ret_gu, 0); \

5
arch/x86/include/asm/xen/hypercall.h
View File

@ -113,10 +113,9 @@ extern struct { char _entry[32]; } hypercall_page[];
register unsigned long __arg2 asm(__HYPERCALL_ARG2REG) = __arg2; \
register unsigned long __arg3 asm(__HYPERCALL_ARG3REG) = __arg3; \
register unsigned long __arg4 asm(__HYPERCALL_ARG4REG) = __arg4; \
register unsigned long __arg5 asm(__HYPERCALL_ARG5REG) = __arg5; \
register void *__sp asm(_ASM_SP);
register unsigned long __arg5 asm(__HYPERCALL_ARG5REG) = __arg5;
#define __HYPERCALL_0PARAM "=r" (__res), "+r" (__sp)
#define __HYPERCALL_0PARAM "=r" (__res), ASM_CALL_CONSTRAINT
#define __HYPERCALL_1PARAM __HYPERCALL_0PARAM, "+r" (__arg1)
#define __HYPERCALL_2PARAM __HYPERCALL_1PARAM, "+r" (__arg2)
#define __HYPERCALL_3PARAM __HYPERCALL_2PARAM, "+r" (__arg3)

8
arch/x86/kernel/cpu/bugs.c
View File

@ -21,14 +21,6 @@
void __init check_bugs(void)
{
#ifdef CONFIG_X86_32
/*
* Regardless of whether PCID is enumerated, the SDM says
* that it can't be enabled in 32-bit mode.
*/
setup_clear_cpu_cap(X86_FEATURE_PCID);
#endif
identify_boot_cpu();
if (!IS_ENABLED(CONFIG_SMP)) {

8
arch/x86/kernel/cpu/common.c
View File

@ -904,6 +904,14 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
setup_force_cpu_cap(X86_FEATURE_ALWAYS);
fpu__init_system(c);
#ifdef CONFIG_X86_32
/*
* Regardless of whether PCID is enumerated, the SDM says
* that it can't be enabled in 32-bit mode.
*/
setup_clear_cpu_cap(X86_FEATURE_PCID);
#endif
}
void __init early_cpu_init(void)

13
arch/x86/kernel/smpboot.c
View File

@ -232,12 +232,6 @@ static void notrace start_secondary(void *unused)
*/
if (boot_cpu_has(X86_FEATURE_PCID))
__write_cr4(__read_cr4() | X86_CR4_PCIDE);
cpu_init();
x86_cpuinit.early_percpu_clock_init();
preempt_disable();
smp_callin();
enable_start_cpu0 = 0;
#ifdef CONFIG_X86_32
/* switch away from the initial page table */
@ -245,6 +239,13 @@ static void notrace start_secondary(void *unused)
__flush_tlb_all();
#endif
cpu_init();
x86_cpuinit.early_percpu_clock_init();
preempt_disable();
smp_callin();
enable_start_cpu0 = 0;
/* otherwise gcc will move up smp_processor_id before the cpu_init */
barrier();
/*

3
arch/x86/kvm/emulate.c
View File

@ -5298,7 +5298,6 @@ static void fetch_possible_mmx_operand(struct x86_emulate_ctxt *ctxt,
static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *))
{
register void *__sp asm(_ASM_SP);
ulong flags = (ctxt->eflags & EFLAGS_MASK) | X86_EFLAGS_IF;
if (!(ctxt->d & ByteOp))
@ -5306,7 +5305,7 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *))
asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n"
: "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags),
[fastop]"+S"(fop), "+r"(__sp)
[fastop]"+S"(fop), ASM_CALL_CONSTRAINT
: "c"(ctxt->src2.val));
ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK);

3
arch/x86/kvm/vmx.c
View File

@ -9045,7 +9045,6 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
{
u32 exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
register void *__sp asm(_ASM_SP);
if ((exit_intr_info & (INTR_INFO_VALID_MASK | INTR_INFO_INTR_TYPE_MASK))
== (INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR)) {
@ -9074,7 +9073,7 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
#ifdef CONFIG_X86_64
[sp]"=&r"(tmp),
#endif
"+r"(__sp)
ASM_CALL_CONSTRAINT
:
[entry]"r"(entry),
[ss]"i"(__KERNEL_DS),

3
arch/x86/mm/fault.c
View File

@ -806,7 +806,6 @@ no_context(struct pt_regs *regs, unsigned long error_code,
if (is_vmalloc_addr((void *)address) &&
(((unsigned long)tsk->stack - 1 - address < PAGE_SIZE) ||
address - ((unsigned long)tsk->stack + THREAD_SIZE) < PAGE_SIZE)) {
register void *__sp asm("rsp");
unsigned long stack = this_cpu_read(orig_ist.ist[DOUBLEFAULT_STACK]) - sizeof(void *);
/*
* We're likely to be running with very little stack space
@ -821,7 +820,7 @@ no_context(struct pt_regs *regs, unsigned long error_code,
asm volatile ("movq %[stack], %%rsp\n\t"
"call handle_stack_overflow\n\t"
"1: jmp 1b"
: "+r" (__sp)
: ASM_CALL_CONSTRAINT
: "D" ("kernel stack overflow (page fault)"),
"S" (regs), "d" (address),
[stack] "rm" (stack));

11
arch/x86/mm/tlb.c
View File

@ -126,8 +126,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
* isn't free.
*/
#ifdef CONFIG_DEBUG_VM
if (WARN_ON_ONCE(__read_cr3() !=
(__sme_pa(real_prev->pgd) | prev_asid))) {
if (WARN_ON_ONCE(__read_cr3() != build_cr3(real_prev, prev_asid))) {
/*
* If we were to BUG here, we'd be very likely to kill
* the system so hard that we don't see the call trace.
@ -172,7 +171,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
*/
this_cpu_write(cpu_tlbstate.ctxs[prev_asid].tlb_gen,
next_tlb_gen);
write_cr3(__sme_pa(next->pgd) | prev_asid);
write_cr3(build_cr3(next, prev_asid));
trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH,
TLB_FLUSH_ALL);
}
@ -216,12 +215,12 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
if (need_flush) {
this_cpu_write(cpu_tlbstate.ctxs[new_asid].ctx_id, next->context.ctx_id);
this_cpu_write(cpu_tlbstate.ctxs[new_asid].tlb_gen, next_tlb_gen);
write_cr3(__sme_pa(next->pgd) | new_asid);
write_cr3(build_cr3(next, new_asid));
trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH,
TLB_FLUSH_ALL);
} else {
/* The new ASID is already up to date. */
write_cr3(__sme_pa(next->pgd) | new_asid | CR3_NOFLUSH);
write_cr3(build_cr3_noflush(next, new_asid));
trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, 0);
}
@ -265,7 +264,7 @@ void initialize_tlbstate_and_flush(void)
!(cr4_read_shadow() & X86_CR4_PCIDE));
/* Force ASID 0 and force a TLB flush. */
write_cr3(cr3 & ~CR3_PCID_MASK);
write_cr3(build_cr3(mm, 0));
/* Reinitialize tlbstate. */
this_cpu_write(cpu_tlbstate.loaded_mm_asid, 0);

6
tools/objtool/Documentation/stack-validation.txt
View File

@ -194,10 +194,10 @@ they mean, and suggestions for how to fix them.
If it's a GCC-compiled .c file, the error may be because the function
uses an inline asm() statement which has a "call" instruction. An
asm() statement with a call instruction must declare the use of the
stack pointer in its output operand. For example, on x86_64:
stack pointer in its output operand. On x86_64, this means adding
the ASM_CALL_CONSTRAINT as an output constraint:
register void *__sp asm("rsp");
asm volatile("call func" : "+r" (__sp));
asm volatile("call func" : ASM_CALL_CONSTRAINT);
Otherwise the stack frame may not get created before the call.

6
tools/objtool/arch/x86/decode.c
View File

@ -208,14 +208,14 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
break;
case 0x89:
if (rex == 0x48 && modrm == 0xe5) {
if (rex_w && !rex_r && modrm_mod == 3 && modrm_reg == 4) {
/* mov %rsp, %rbp */
/* mov %rsp, reg */
*type = INSN_STACK;
op->src.type = OP_SRC_REG;
op->src.reg = CFI_SP;
op->dest.type = OP_DEST_REG;
op->dest.reg = CFI_BP;
op->dest.reg = op_to_cfi_reg[modrm_rm][rex_b];
break;
}

43
tools/objtool/check.c
View File

@ -1203,24 +1203,39 @@ static int update_insn_state(struct instruction *insn, struct insn_state *state)
switch (op->src.type) {
case OP_SRC_REG:
if (op->src.reg == CFI_SP && op->dest.reg == CFI_BP) {
if (op->src.reg == CFI_SP && op->dest.reg == CFI_BP &&
cfa->base == CFI_SP &&
regs[CFI_BP].base == CFI_CFA &&
regs[CFI_BP].offset == -cfa->offset) {
if (cfa->base == CFI_SP &&
regs[CFI_BP].base == CFI_CFA &&
regs[CFI_BP].offset == -cfa->offset) {
/* mov %rsp, %rbp */
cfa->base = op->dest.reg;
state->bp_scratch = false;
}
/* mov %rsp, %rbp */
cfa->base = op->dest.reg;
state->bp_scratch = false;
}
else if (op->src.reg == CFI_SP &&
op->dest.reg == CFI_BP && state->drap) {
else if (state->drap) {
/* drap: mov %rsp, %rbp */
regs[CFI_BP].base = CFI_BP;
regs[CFI_BP].offset = -state->stack_size;
state->bp_scratch = false;
}
/* drap: mov %rsp, %rbp */
regs[CFI_BP].base = CFI_BP;
regs[CFI_BP].offset = -state->stack_size;
state->bp_scratch = false;
}
else if (op->src.reg == CFI_SP && cfa->base == CFI_SP) {
/*
* mov %rsp, %reg
*
* This is needed for the rare case where GCC
* does:
*
* mov %rsp, %rax
* ...
* mov %rax, %rsp
*/
state->vals[op->dest.reg].base = CFI_CFA;
state->vals[op->dest.reg].offset = -state->stack_size;
}
else if (op->dest.reg == cfa->base) {