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authorLinus Torvalds <torvalds@linux-foundation.org>2020-10-27 14:39:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-27 14:39:29 -0700
commited8780e3f2ecc82645342d070c6b4e530532e680 (patch)
tree3a9b69695e08bab76dc283286404b52ff8c3c1bc /arch
parent8c2ab803e565f994b897573f6f2f6520eef41159 (diff)
parentabee7c494d8c41bb388839bccc47e06247f0d7de (diff)
downloadlinux-stericsson-ed8780e3f2ecc82645342d070c6b4e530532e680.tar.gz
Merge tag 'x86-urgent-2020-10-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner: "A couple of x86 fixes which missed rc1 due to my stupidity: - Drop lazy TLB mode before switching to the temporary address space for text patching. text_poke() switches to the temporary mm which clears the lazy mode and restores the original mm afterwards. Due to clearing lazy mode this might restore a already dead mm if exit_mmap() runs in parallel on another CPU. - Document the x32 syscall design fail vs. syscall numbers 512-547 properly. - Fix the ORC unwinder to handle the inactive task frame correctly. This was unearthed due to the slightly different code generation of gcc-10. - Use an up to date screen_info for the boot params of kexec instead of the possibly stale and invalid version which happened to be valid when the kexec kernel was loaded" * tag 'x86-urgent-2020-10-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/alternative: Don't call text_poke() in lazy TLB mode x86/syscalls: Document the fact that syscalls 512-547 are a legacy mistake x86/unwind/orc: Fix inactive tasks with stack pointer in %sp on GCC 10 compiled kernels hyperv_fb: Update screen_info after removing old framebuffer x86/kexec: Use up-to-dated screen_info copy to fill boot params
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/entry/syscalls/syscall_64.tbl10
-rw-r--r--arch/x86/kernel/alternative.c9
-rw-r--r--arch/x86/kernel/kexec-bzimage64.c3
-rw-r--r--arch/x86/kernel/unwind_orc.c9
4 files changed, 17 insertions, 14 deletions
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 1f47e24fb65c..379819244b91 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -364,10 +364,10 @@
440 common process_madvise sys_process_madvise
#
-# x32-specific system call numbers start at 512 to avoid cache impact
-# for native 64-bit operation. The __x32_compat_sys stubs are created
-# on-the-fly for compat_sys_*() compatibility system calls if X86_X32
-# is defined.
+# Due to a historical design error, certain syscalls are numbered differently
+# in x32 as compared to native x86_64. These syscalls have numbers 512-547.
+# Do not add new syscalls to this range. Numbers 548 and above are available
+# for non-x32 use.
#
512 x32 rt_sigaction compat_sys_rt_sigaction
513 x32 rt_sigreturn compat_sys_x32_rt_sigreturn
@@ -405,3 +405,5 @@
545 x32 execveat compat_sys_execveat
546 x32 preadv2 compat_sys_preadv64v2
547 x32 pwritev2 compat_sys_pwritev64v2
+# This is the end of the legacy x32 range. Numbers 548 and above are
+# not special and are not to be used for x32-specific syscalls.
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 4adbe65afe23..2400ad62f330 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -807,6 +807,15 @@ static inline temp_mm_state_t use_temporary_mm(struct mm_struct *mm)
temp_mm_state_t temp_state;
lockdep_assert_irqs_disabled();
+
+ /*
+ * Make sure not to be in TLB lazy mode, as otherwise we'll end up
+ * with a stale address space WITHOUT being in lazy mode after
+ * restoring the previous mm.
+ */
+ if (this_cpu_read(cpu_tlbstate.is_lazy))
+ leave_mm(smp_processor_id());
+
temp_state.mm = this_cpu_read(cpu_tlbstate.loaded_mm);
switch_mm_irqs_off(NULL, mm, current);
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 57c2ecf43134..ce831f9448e7 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -200,8 +200,7 @@ setup_boot_parameters(struct kimage *image, struct boot_params *params,
params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
/* Copying screen_info will do? */
- memcpy(&params->screen_info, &boot_params.screen_info,
- sizeof(struct screen_info));
+ memcpy(&params->screen_info, &screen_info, sizeof(struct screen_info));
/* Fill in memsize later */
params->screen_info.ext_mem_k = 0;
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 6a339ce328e0..73f800100066 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -321,19 +321,12 @@ EXPORT_SYMBOL_GPL(unwind_get_return_address);
unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
{
- struct task_struct *task = state->task;
-
if (unwind_done(state))
return NULL;
if (state->regs)
return &state->regs->ip;
- if (task != current && state->sp == task->thread.sp) {
- struct inactive_task_frame *frame = (void *)task->thread.sp;
- return &frame->ret_addr;
- }
-
if (state->sp)
return (unsigned long *)state->sp - 1;
@@ -663,7 +656,7 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
} else {
struct inactive_task_frame *frame = (void *)task->thread.sp;
- state->sp = task->thread.sp;
+ state->sp = task->thread.sp + sizeof(*frame);
state->bp = READ_ONCE_NOCHECK(frame->bp);
state->ip = READ_ONCE_NOCHECK(frame->ret_addr);
state->signal = (void *)state->ip == ret_from_fork;