This is a note to let you know that I've just added the patch titled
x86/ibt,paravirt: Use text_gen_insn() for paravirt_patch()
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-ibt-paravirt-use-text_gen_insn-for-paravirt_patch.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From fa9d1e9927ed5387d324b2d8cd04f106c89cb507 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Tue, 8 Mar 2022 16:30:20 +0100
Subject: x86/ibt,paravirt: Use text_gen_insn() for paravirt_patch()
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Upstream commit: ba27d1a80871eb8dbeddf34ec7d396c149cbb8d7
Less duplication is more better.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220308154317.697253958@xxxxxxxxxxxxx
[ Keep struct branch. ]
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/text-patching.h | 20 ++++++++++++++------
arch/x86/kernel/paravirt.c | 22 +++++-----------------
2 files changed, 19 insertions(+), 23 deletions(-)
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -96,32 +96,40 @@ union text_poke_insn {
};
static __always_inline
-void *text_gen_insn(u8 opcode, const void *addr, const void *dest)
+void __text_gen_insn(void *buf, u8 opcode, const void *addr, const void *dest, int size)
{
- static union text_poke_insn insn; /* per instance */
- int size = text_opcode_size(opcode);
+ union text_poke_insn *insn = buf;
+
+ BUG_ON(size < text_opcode_size(opcode));
/*
* Hide the addresses to avoid the compiler folding in constants when
* referencing code, these can mess up annotations like
* ANNOTATE_NOENDBR.
*/
+ OPTIMIZER_HIDE_VAR(insn);
OPTIMIZER_HIDE_VAR(addr);
OPTIMIZER_HIDE_VAR(dest);
- insn.opcode = opcode;
+ insn->opcode = opcode;
if (size > 1) {
- insn.disp = (long)dest - (long)(addr + size);
+ insn->disp = (long)dest - (long)(addr + size);
if (size == 2) {
/*
* Ensure that for JMP8 the displacement
* actually fits the signed byte.
*/
- BUG_ON((insn.disp >> 31) != (insn.disp >> 7));
+ BUG_ON((insn->disp >> 31) != (insn->disp >> 7));
}
}
+}
+static __always_inline
+void *text_gen_insn(u8 opcode, const void *addr, const void *dest)
+{
+ static union text_poke_insn insn; /* per instance */
+ __text_gen_insn(&insn, opcode, addr, dest, text_opcode_size(opcode));
return &insn.text;
}
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -55,28 +55,16 @@ void __init default_banner(void)
static const unsigned char ud2a[] = { 0x0f, 0x0b };
struct branch {
- unsigned char opcode;
- u32 delta;
+ unsigned char opcode;
+ u32 delta;
} __attribute__((packed));
static unsigned paravirt_patch_call(void *insn_buff, const void *target,
unsigned long addr, unsigned len)
{
- const int call_len = 5;
- struct branch *b = insn_buff;
- unsigned long delta = (unsigned long)target - (addr+call_len);
-
- if (len < call_len) {
- pr_warn("paravirt: Failed to patch indirect CALL at %ps\n", (void *)addr);
- /* Kernel might not be viable if patching fails, bail out: */
- BUG_ON(1);
- }
-
- b->opcode = 0xe8; /* call */
- b->delta = delta;
- BUILD_BUG_ON(sizeof(*b) != call_len);
-
- return call_len;
+ __text_gen_insn(insn_buff, CALL_INSN_OPCODE,
+ (void *)addr, target, CALL_INSN_SIZE);
+ return CALL_INSN_SIZE;
}
#ifdef CONFIG_PARAVIRT_XXL
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-5.10/x86-ftrace-use-alternative-ret-encoding.patch
queue-5.10/x86-uaccess-implement-macros-for-cmpxchg-on-user-add.patch
queue-5.10/x86-text-patching-make-text_gen_insn-play-nice-with-annotate_noendbr.patch
queue-5.10/x86-alternative-make-custom-return-thunk-unconditional.patch
queue-5.10/task_stack-x86-cea-force-inline-stack-helpers.patch
queue-5.10/x86-returnthunk-allow-different-return-thunks.patch
queue-5.10/x86-ibt-paravirt-use-text_gen_insn-for-paravirt_patch.patch
queue-5.10/sched-rt-fix-sysctl_sched_rr_timeslice-intial-value.patch
queue-5.10/sched-rt-sysctl_sched_rr_timeslice-show-default-timeslice-after-reset.patch
