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Message-Id: <20230211091302.4576-1-lina@asahilina.net>
Date: Sat, 11 Feb 2023 18:13:02 +0900
From: Asahi Lina <lina@...hilina.net>
To: Arnd Bergmann <arnd@...db.de>, Hector Martin <marcan@...can.st>,
Sven Peter <sven@...npeter.dev>
Cc: Alyssa Rosenzweig <alyssa@...enzweig.io>, asahi@...ts.linux.dev,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
Asahi Lina <lina@...hilina.net>
Subject: [PATCH] soc: apple: rtkit: Do not copy the reg state structure to the stack
The register state struct is 848 bytes, which ends up bloating the
apple_rtkit_crashlog_dump_regs stack frame beyond 1024 on some
32-bit platforms, triggering compile warnings.
This doesn't matter for 64BIT/ARM64, but there's also no good reason to
copy the structure to the stack in this case. We can use __packed to
avoid alignment issues, there are no double-read hazards, and this is a
fatal error path so performance does not matter.
Fixes: 22991d8d5725 ("soc: apple: rtkit: Add register dump decoding to crashlog")
Signed-off-by: Asahi Lina <lina@...hilina.net>
---
drivers/soc/apple/rtkit-crashlog.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/drivers/soc/apple/rtkit-crashlog.c b/drivers/soc/apple/rtkit-crashlog.c
index dfa74b32eda2..8319e365110b 100644
--- a/drivers/soc/apple/rtkit-crashlog.c
+++ b/drivers/soc/apple/rtkit-crashlog.c
@@ -57,7 +57,7 @@ struct apple_rtkit_crashlog_regs {
u64 unk_X;
u64 esr;
u64 unk_Z;
-};
+} __packed;
static_assert(sizeof(struct apple_rtkit_crashlog_regs) == 0x350);
static void apple_rtkit_crashlog_dump_str(struct apple_rtkit *rtk, u8 *bfr,
@@ -126,18 +126,18 @@ static void apple_rtkit_crashlog_dump_mailbox(struct apple_rtkit *rtk, u8 *bfr,
static void apple_rtkit_crashlog_dump_regs(struct apple_rtkit *rtk, u8 *bfr,
size_t size)
{
- struct apple_rtkit_crashlog_regs regs;
+ struct apple_rtkit_crashlog_regs *regs;
const char *el;
int i;
- if (size < sizeof(regs)) {
+ if (size < sizeof(*regs)) {
dev_warn(rtk->dev, "RTKit: Regs section too small: 0x%zx", size);
return;
}
- memcpy(®s, bfr, sizeof(regs));
+ regs = (struct apple_rtkit_crashlog_regs *)bfr;
- switch (regs.psr & PSR_MODE_MASK) {
+ switch (regs->psr & PSR_MODE_MASK) {
case PSR_MODE_EL0t:
el = "EL0t";
break;
@@ -160,11 +160,11 @@ static void apple_rtkit_crashlog_dump_regs(struct apple_rtkit *rtk, u8 *bfr,
dev_warn(rtk->dev, "RTKit: Exception dump:");
dev_warn(rtk->dev, " == Exception taken from %s ==", el);
- dev_warn(rtk->dev, " PSR = 0x%llx", regs.psr);
- dev_warn(rtk->dev, " PC = 0x%llx\n", regs.pc);
- dev_warn(rtk->dev, " ESR = 0x%llx\n", regs.esr);
- dev_warn(rtk->dev, " FAR = 0x%llx\n", regs.far);
- dev_warn(rtk->dev, " SP = 0x%llx\n", regs.sp);
+ dev_warn(rtk->dev, " PSR = 0x%llx", regs->psr);
+ dev_warn(rtk->dev, " PC = 0x%llx\n", regs->pc);
+ dev_warn(rtk->dev, " ESR = 0x%llx\n", regs->esr);
+ dev_warn(rtk->dev, " FAR = 0x%llx\n", regs->far);
+ dev_warn(rtk->dev, " SP = 0x%llx\n", regs->sp);
dev_warn(rtk->dev, "\n");
for (i = 0; i < 31; i += 4) {
@@ -172,12 +172,12 @@ static void apple_rtkit_crashlog_dump_regs(struct apple_rtkit *rtk, u8 *bfr,
dev_warn(rtk->dev,
" x%02d-x%02d = %016llx %016llx %016llx %016llx\n",
i, i + 3,
- regs.regs[i], regs.regs[i + 1],
- regs.regs[i + 2], regs.regs[i + 3]);
+ regs->regs[i], regs->regs[i + 1],
+ regs->regs[i + 2], regs->regs[i + 3]);
else
dev_warn(rtk->dev,
" x%02d-x%02d = %016llx %016llx %016llx\n", i, i + 3,
- regs.regs[i], regs.regs[i + 1], regs.regs[i + 2]);
+ regs->regs[i], regs->regs[i + 1], regs->regs[i + 2]);
}
dev_warn(rtk->dev, "\n");
--
2.35.1
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