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Message-ID: <20250327205355.378659-33-mingo@kernel.org>
Date: Thu, 27 Mar 2025 21:53:45 +0100
From: Ingo Molnar <mingo@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: Juergen Gross <jgross@...e.com>,
"H . Peter Anvin" <hpa@...or.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Borislav Petkov <bp@...en8.de>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 32/41] x86/alternatives: Simplify text_poke_int3_batch()
This function is now using the tp_array state exclusively,
make that explicit by removing the redundant input parameters.
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
arch/x86/kernel/alternative.c | 43 ++++++++++++++++++++-----------------------
1 file changed, 20 insertions(+), 23 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 9402826e2903..40e86b41bb86 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2591,8 +2591,8 @@ noinstr int text_poke_int3_handler(struct pt_regs *regs)
/**
* text_poke_int3_batch() -- update instructions on live kernel on SMP
- * @tp: vector of instructions to patch
- * @nr_entries: number of entries in the vector
+ * @tp_array.vec: vector of instructions to patch
+ * @tp_array.nr_entries: number of entries in the vector
*
* Modify multi-byte instruction by using int3 breakpoint on SMP.
* We completely avoid stop_machine() here, and achieve the
@@ -2610,7 +2610,7 @@ noinstr int text_poke_int3_handler(struct pt_regs *regs)
* replacing opcode
* - sync cores
*/
-static void text_poke_int3_batch(struct text_poke_int3_loc *tp, unsigned int nr_entries)
+static void text_poke_int3_batch(void)
{
unsigned char int3 = INT3_INSN_OPCODE;
unsigned int i;
@@ -2618,9 +2618,6 @@ static void text_poke_int3_batch(struct text_poke_int3_loc *tp, unsigned int nr_
lockdep_assert_held(&text_mutex);
- WARN_ON_ONCE(tp != tp_array.vec);
- WARN_ON_ONCE(nr_entries != tp_array.nr_entries);
-
/*
* Corresponds to the implicit memory barrier in try_get_tp_array() to
* ensure reading a non-zero refcount provides up to date tp_array data.
@@ -2640,16 +2637,16 @@ static void text_poke_int3_batch(struct text_poke_int3_loc *tp, unsigned int nr_
/*
* Corresponding read barrier in int3 notifier for making sure the
- * nr_entries and handler are correctly ordered wrt. patching.
+ * tp_array.nr_entries and handler are correctly ordered wrt. patching.
*/
smp_wmb();
/*
* First step: add a int3 trap to the address that will be patched.
*/
- for (i = 0; i < nr_entries; i++) {
- tp[i].old = *(u8 *)text_poke_int3_addr(&tp[i]);
- text_poke(text_poke_int3_addr(&tp[i]), &int3, INT3_INSN_SIZE);
+ for (i = 0; i < tp_array.nr_entries; i++) {
+ tp_array.vec[i].old = *(u8 *)text_poke_int3_addr(&tp_array.vec[i]);
+ text_poke(text_poke_int3_addr(&tp_array.vec[i]), &int3, INT3_INSN_SIZE);
}
text_poke_sync();
@@ -2657,15 +2654,15 @@ static void text_poke_int3_batch(struct text_poke_int3_loc *tp, unsigned int nr_
/*
* Second step: update all but the first byte of the patched range.
*/
- for (do_sync = 0, i = 0; i < nr_entries; i++) {
- u8 old[POKE_MAX_OPCODE_SIZE+1] = { tp[i].old, };
+ for (do_sync = 0, i = 0; i < tp_array.nr_entries; i++) {
+ u8 old[POKE_MAX_OPCODE_SIZE+1] = { tp_array.vec[i].old, };
u8 _new[POKE_MAX_OPCODE_SIZE+1];
- const u8 *new = tp[i].text;
- int len = tp[i].len;
+ const u8 *new = tp_array.vec[i].text;
+ int len = tp_array.vec[i].len;
if (len - INT3_INSN_SIZE > 0) {
memcpy(old + INT3_INSN_SIZE,
- text_poke_int3_addr(&tp[i]) + INT3_INSN_SIZE,
+ text_poke_int3_addr(&tp_array.vec[i]) + INT3_INSN_SIZE,
len - INT3_INSN_SIZE);
if (len == 6) {
@@ -2674,7 +2671,7 @@ static void text_poke_int3_batch(struct text_poke_int3_loc *tp, unsigned int nr_
new = _new;
}
- text_poke(text_poke_int3_addr(&tp[i]) + INT3_INSN_SIZE,
+ text_poke(text_poke_int3_addr(&tp_array.vec[i]) + INT3_INSN_SIZE,
new + INT3_INSN_SIZE,
len - INT3_INSN_SIZE);
@@ -2705,7 +2702,7 @@ static void text_poke_int3_batch(struct text_poke_int3_loc *tp, unsigned int nr_
* The old instruction is recorded so that the event can be
* processed forwards or backwards.
*/
- perf_event_text_poke(text_poke_int3_addr(&tp[i]), old, len, new, len);
+ perf_event_text_poke(text_poke_int3_addr(&tp_array.vec[i]), old, len, new, len);
}
if (do_sync) {
@@ -2721,16 +2718,16 @@ static void text_poke_int3_batch(struct text_poke_int3_loc *tp, unsigned int nr_
* Third step: replace the first byte (int3) by the first byte of
* replacing opcode.
*/
- for (do_sync = 0, i = 0; i < nr_entries; i++) {
- u8 byte = tp[i].text[0];
+ for (do_sync = 0, i = 0; i < tp_array.nr_entries; i++) {
+ u8 byte = tp_array.vec[i].text[0];
- if (tp[i].len == 6)
+ if (tp_array.vec[i].len == 6)
byte = 0x0f;
if (byte == INT3_INSN_OPCODE)
continue;
- text_poke(text_poke_int3_addr(&tp[i]), &byte, INT3_INSN_SIZE);
+ text_poke(text_poke_int3_addr(&tp_array.vec[i]), &byte, INT3_INSN_SIZE);
do_sync++;
}
@@ -2859,7 +2856,7 @@ static bool tp_addr_ordered(void *addr)
void text_poke_int3_finish(void)
{
if (tp_array.nr_entries) {
- text_poke_int3_batch(tp_array.vec, tp_array.nr_entries);
+ text_poke_int3_batch();
tp_array.nr_entries = 0;
}
}
@@ -2869,7 +2866,7 @@ static void text_poke_int3_flush(void *addr)
lockdep_assert_held(&text_mutex);
if (tp_array.nr_entries == TP_ARRAY_NR_ENTRIES_MAX || !tp_addr_ordered(addr)) {
- text_poke_int3_batch(tp_array.vec, tp_array.nr_entries);
+ text_poke_int3_batch();
tp_array.nr_entries = 0;
}
}
--
2.45.2
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