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Message-Id: <20231122092855.4440-3-shijie@os.amperecomputing.com>
Date: Wed, 22 Nov 2023 17:28:53 +0800
From: Huang Shijie <shijie@...amperecomputing.com>
To: catalin.marinas@....com
Cc: will@...nel.org, mark.rutland@....com, suzuki.poulose@....com,
broonie@...nel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, anshuman.khandual@....com,
robh@...nel.org, oliver.upton@...ux.dev, maz@...nel.org,
patches@...erecomputing.com,
Huang Shijie <shijie@...amperecomputing.com>
Subject: [PATCH 2/4] arm64: alternative: handle the kernel exception table
In arch/arm64/lib/copy_templates.S, some macros involve kernel exception table,
such as ldp1/stp1/strh1/str1,etc. Current alternative_if does not support
to embed them.
This patch adds the support to embed them into alternative_if:
1.) Modify the @insn to the right address,
2.) Sort the kernel exception table.
Signed-off-by: Huang Shijie <shijie@...amperecomputing.com>
---
arch/arm64/kernel/alternative.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c
index 8ff6610af496..4c73f9cc9a85 100644
--- a/arch/arm64/kernel/alternative.c
+++ b/arch/arm64/kernel/alternative.c
@@ -19,6 +19,7 @@
#include <asm/sections.h>
#include <asm/vdso.h>
#include <linux/stop_machine.h>
+#include <linux/extable.h>
#define __ALT_PTR(a, f) ((void *)&(a)->f + (a)->f)
#define ALT_ORIG_PTR(a) __ALT_PTR(a, orig_offset)
@@ -101,6 +102,22 @@ static __always_inline u32 get_alt_insn(struct alt_instr *alt, __le32 *insnptr,
return insn;
}
+/* Check the kernel exception table */
+static void check_extable(__le32 *origptr, __le32 *updptr, __le32 *replptr)
+{
+ struct exception_table_entry *e;
+ unsigned long addr = (unsigned long)replptr;
+
+ e = (struct exception_table_entry *)search_kernel_exception_table(addr);
+ if (e) {
+ /* Modify the @insn to the right address */
+ e->insn = cpu_to_le32((int)((long)(origptr) - (long)(&e->insn)));
+
+ /* Sort the kernel exception table */
+ __sort_main_extable();
+ }
+}
+
static noinstr void patch_alternative(struct alt_instr *alt,
__le32 *origptr, __le32 *updptr, int nr_inst)
{
@@ -112,6 +129,7 @@ static noinstr void patch_alternative(struct alt_instr *alt,
u32 insn;
insn = get_alt_insn(alt, origptr + i, replptr + i);
+ check_extable(origptr + i, updptr + i, replptr + i);
updptr[i] = cpu_to_le32(insn);
}
}
--
2.40.1
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