lkml.org 
[lkml]   [2019]   [Aug]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 2/3] x86/alternatives: Move tp_vec
In order to allow other users to make use of the tp_vec; move it near
the text_poke_bp_batch() code, instead of keeping it in the jump_label
code.

Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/include/asm/text-patching.h | 4 ++++
arch/x86/kernel/alternative.c | 3 +++
arch/x86/kernel/jump_label.c | 25 ++++++++++++-------------
3 files changed, 19 insertions(+), 13 deletions(-)

--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -60,6 +60,10 @@ extern int after_bootmem;
extern __ro_after_init struct mm_struct *poking_mm;
extern __ro_after_init unsigned long poking_addr;

+#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc))
+extern struct text_poke_loc tp_vec[TP_VEC_MAX];
+extern int tp_vec_nr;
+
#ifndef CONFIG_UML_X86
static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
{
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1017,6 +1017,9 @@ int poke_int3_handler(struct pt_regs *re
}
NOKPROBE_SYMBOL(poke_int3_handler);

+struct text_poke_loc tp_vec[TP_VEC_MAX];
+int tp_vec_nr;
+
/**
* text_poke_bp_batch() -- update instructions on live kernel on SMP
* @tp: vector of instructions to patch
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -100,15 +100,12 @@ void arch_jump_label_transform(struct ju
mutex_unlock(&text_mutex);
}

-#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc))
-static struct text_poke_loc tp_vec[TP_VEC_MAX];
-static int tp_vec_nr;
-
bool arch_jump_label_transform_queue(struct jump_entry *entry,
enum jump_label_type type)
{
struct text_poke_loc *tp;
void *entry_code;
+ bool ret = true;

if (system_state == SYSTEM_BOOTING) {
/*
@@ -118,12 +115,15 @@ bool arch_jump_label_transform_queue(str
return true;
}

+ mutex_lock(&text_mutex);
/*
* No more space in the vector, tell upper layer to apply
* the queue before continuing.
*/
- if (tp_vec_nr == TP_VEC_MAX)
- return false;
+ if (tp_vec_nr == TP_VEC_MAX) {
+ ret = false;
+ goto unlock;
+ }

tp = &tp_vec[tp_vec_nr];

@@ -151,20 +151,19 @@ bool arch_jump_label_transform_queue(str
text_poke_loc_init(tp, entry_code, NULL, JUMP_LABEL_NOP_SIZE, NULL);

tp_vec_nr++;
+unlock:
+ mutex_unlock(&text_mutex);

- return true;
+ return ret;
}

void arch_jump_label_transform_apply(void)
{
- if (!tp_vec_nr)
- return;
-
mutex_lock(&text_mutex);
- text_poke_bp_batch(tp_vec, tp_vec_nr);
- mutex_unlock(&text_mutex);
-
+ if (tp_vec_nr)
+ text_poke_bp_batch(tp_vec, tp_vec_nr);
tp_vec_nr = 0;
+ mutex_unlock(&text_mutex);
}

static enum {

\
 
 \ /
  Last update: 2019-08-26 14:58    [W:0.040 / U:0.112 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site