Commit 38e6bf23 authored by Linus Torvalds's avatar Linus Torvalds

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

Pull x86 fixes from Thomas Gleixner:
 "A series of fixes for X86:

   - The final fix for the end-of-stack issue in the unwinder
   - Handle non PAT systems gracefully
   - Prevent access to uninitiliazed memory
   - Move early delay calaibration after basic init
   - Fix Kconfig help text
   - Fix a cross compile issue
   - Unbreak older make versions"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/timers: Move simple_udelay_calibration past init_hypervisor_platform
  x86/alternatives: Prevent uninitialized stack byte read in apply_alternatives()
  x86/PAT: Fix Xorg regression on CPUs that don't support PAT
  x86/watchdog: Fix Kconfig help text file path reference to lockup watchdog documentation
  x86/build: Permit building with old make versions
  x86/unwind: Add end-of-stack check for ftrace handlers
  Revert "x86/entry: Fix the end of the stack for newly forked tasks"
  x86/boot: Use CROSS_COMPILE prefix for readelf
parents 39b8ab31 702644ec
......@@ -360,7 +360,7 @@ config SMP
Management" code will be disabled if you say Y here.
See also <file:Documentation/x86/i386/IO-APIC.txt>,
<file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
<file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
<http://www.tldp.org/docs.html#howto>.
If you don't know what to do here, say N.
......
......@@ -94,7 +94,7 @@ vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_thunk_$(BITS).o
quiet_cmd_check_data_rel = DATAREL $@
define cmd_check_data_rel
for obj in $(filter %.o,$^); do \
readelf -S $$obj | grep -qF .rel.local && { \
${CROSS_COMPILE}readelf -S $$obj | grep -qF .rel.local && { \
echo "error: $$obj has data relocations!" >&2; \
exit 1; \
} || true; \
......
......@@ -251,6 +251,23 @@ ENTRY(__switch_to_asm)
jmp __switch_to
END(__switch_to_asm)
/*
* The unwinder expects the last frame on the stack to always be at the same
* offset from the end of the page, which allows it to validate the stack.
* Calling schedule_tail() directly would break that convention because its an
* asmlinkage function so its argument has to be pushed on the stack. This
* wrapper creates a proper "end of stack" frame header before the call.
*/
ENTRY(schedule_tail_wrapper)
FRAME_BEGIN
pushl %eax
call schedule_tail
popl %eax
FRAME_END
ret
ENDPROC(schedule_tail_wrapper)
/*
* A newly forked process directly context switches into this address.
*
......@@ -259,24 +276,15 @@ END(__switch_to_asm)
* edi: kernel thread arg
*/
ENTRY(ret_from_fork)
FRAME_BEGIN /* help unwinder find end of stack */
/*
* schedule_tail() is asmlinkage so we have to put its 'prev' argument
* on the stack.
*/
pushl %eax
call schedule_tail
popl %eax
call schedule_tail_wrapper
testl %ebx, %ebx
jnz 1f /* kernel threads are uncommon */
2:
/* When we fork, we trace the syscall return in the child, too. */
leal FRAME_OFFSET(%esp), %eax
movl %esp, %eax
call syscall_return_slowpath
FRAME_END
jmp restore_all
/* kernel thread */
......
......@@ -36,7 +36,6 @@
#include <asm/smap.h>
#include <asm/pgtable_types.h>
#include <asm/export.h>
#include <asm/frame.h>
#include <linux/err.h>
.code64
......@@ -406,7 +405,6 @@ END(__switch_to_asm)
* r12: kernel thread arg
*/
ENTRY(ret_from_fork)
FRAME_BEGIN /* help unwinder find end of stack */
movq %rax, %rdi
call schedule_tail /* rdi: 'prev' task parameter */
......@@ -414,11 +412,10 @@ ENTRY(ret_from_fork)
jnz 1f /* kernel threads are uncommon */
2:
leaq FRAME_OFFSET(%rsp),%rdi /* pt_regs pointer */
movq %rsp, %rdi
call syscall_return_slowpath /* returns with IRQs disabled */
TRACE_IRQS_ON /* user mode is traced as IRQS on */
SWAPGS
FRAME_END
jmp restore_regs_and_iret
1:
......
......@@ -409,8 +409,13 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
memcpy(insnbuf, replacement, a->replacementlen);
insnbuf_sz = a->replacementlen;
/* 0xe8 is a relative jump; fix the offset. */
if (*insnbuf == 0xe8 && a->replacementlen == 5) {
/*
* 0xe8 is a relative jump; fix the offset.
*
* Instruction length is checked before the opcode to avoid
* accessing uninitialized bytes for zero-length replacements.
*/
if (a->replacementlen == 5 && *insnbuf == 0xe8) {
*(s32 *)(insnbuf + 1) += replacement - instr;
DPRINTK("Fix CALL offset: 0x%x, CALL 0x%lx",
*(s32 *)(insnbuf + 1),
......
......@@ -980,8 +980,6 @@ void __init setup_arch(char **cmdline_p)
*/
x86_configure_nx();
simple_udelay_calibration();
parse_early_param();
#ifdef CONFIG_MEMORY_HOTPLUG
......@@ -1041,6 +1039,8 @@ void __init setup_arch(char **cmdline_p)
*/
init_hypervisor_platform();
simple_udelay_calibration();
x86_init.resources.probe_roms();
/* after parse_early_param, so could debug it */
......
......@@ -104,6 +104,11 @@ static inline unsigned long *last_frame(struct unwind_state *state)
return (unsigned long *)task_pt_regs(state->task) - 2;
}
static bool is_last_frame(struct unwind_state *state)
{
return state->bp == last_frame(state);
}
#ifdef CONFIG_X86_32
#define GCC_REALIGN_WORDS 3
#else
......@@ -115,16 +120,15 @@ static inline unsigned long *last_aligned_frame(struct unwind_state *state)
return last_frame(state) - GCC_REALIGN_WORDS;
}
static bool is_last_task_frame(struct unwind_state *state)
static bool is_last_aligned_frame(struct unwind_state *state)
{
unsigned long *last_bp = last_frame(state);
unsigned long *aligned_bp = last_aligned_frame(state);
/*
* We have to check for the last task frame at two different locations
* because gcc can occasionally decide to realign the stack pointer and
* change the offset of the stack frame in the prologue of a function
* called by head/entry code. Examples:
* GCC can occasionally decide to realign the stack pointer and change
* the offset of the stack frame in the prologue of a function called
* by head/entry code. Examples:
*
* <start_secondary>:
* push %edi
......@@ -141,11 +145,38 @@ static bool is_last_task_frame(struct unwind_state *state)
* push %rbp
* mov %rsp,%rbp
*
* Note that after aligning the stack, it pushes a duplicate copy of
* the return address before pushing the frame pointer.
* After aligning the stack, it pushes a duplicate copy of the return
* address before pushing the frame pointer.
*/
return (state->bp == aligned_bp && *(aligned_bp + 1) == *(last_bp + 1));
}
static bool is_last_ftrace_frame(struct unwind_state *state)
{
unsigned long *last_bp = last_frame(state);
unsigned long *last_ftrace_bp = last_bp - 3;
/*
* When unwinding from an ftrace handler of a function called by entry
* code, the stack layout of the last frame is:
*
* bp
* parent ret addr
* bp
* function ret addr
* parent ret addr
* pt_regs
* -----------------
*/
return (state->bp == last_bp ||
(state->bp == aligned_bp && *(aligned_bp+1) == *(last_bp+1)));
return (state->bp == last_ftrace_bp &&
*state->bp == *(state->bp + 2) &&
*(state->bp + 1) == *(state->bp + 4));
}
static bool is_last_task_frame(struct unwind_state *state)
{
return is_last_frame(state) || is_last_aligned_frame(state) ||
is_last_ftrace_frame(state);
}
/*
......
......@@ -65,9 +65,11 @@ static int __init nopat(char *str)
}
early_param("nopat", nopat);
static bool __read_mostly __pat_initialized = false;
bool pat_enabled(void)
{
return !!__pat_enabled;
return __pat_initialized;
}
EXPORT_SYMBOL_GPL(pat_enabled);
......@@ -225,13 +227,14 @@ static void pat_bsp_init(u64 pat)
}
wrmsrl(MSR_IA32_CR_PAT, pat);
__pat_initialized = true;
__init_cache_modes(pat);
}
static void pat_ap_init(u64 pat)
{
if (!boot_cpu_has(X86_FEATURE_PAT)) {
if (!this_cpu_has(X86_FEATURE_PAT)) {
/*
* If this happens we are on a secondary CPU, but switched to
* PAT on the boot CPU. We have no way to undo PAT.
......@@ -306,7 +309,7 @@ void pat_init(void)
u64 pat;
struct cpuinfo_x86 *c = &boot_cpu_data;
if (!pat_enabled()) {
if (!__pat_enabled) {
init_cache_modes();
return;
}
......
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