[RFC PATCH v2 1/8] arm64: Move patching utilities out of instruction encoding/decoding
Julien Thierry
jthierry at redhat.com
Wed Mar 3 17:05:29 GMT 2021
Files insn.[c|h] containt some functions used for instruction patching.
In order to reuse the instruction encoder/decoder, move the patching
utilities to their own file.
Signed-off-by: Julien Thierry <jthierry at redhat.com>
---
arch/arm64/include/asm/insn.h | 5 -
arch/arm64/include/asm/patching.h | 13 +++
arch/arm64/kernel/Makefile | 2 +-
arch/arm64/kernel/ftrace.c | 1 +
arch/arm64/kernel/insn.c | 149 +-----------------------------
arch/arm64/kernel/jump_label.c | 1 +
arch/arm64/kernel/patching.c | 148 +++++++++++++++++++++++++++++
arch/arm64/kernel/traps.c | 1 +
8 files changed, 168 insertions(+), 152 deletions(-)
create mode 100644 arch/arm64/include/asm/patching.h
create mode 100644 arch/arm64/kernel/patching.c
diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 4ebb9c054ccc..7437b7e7e7eb 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -379,8 +379,6 @@ static inline bool aarch64_insn_is_adr_adrp(u32 insn)
return aarch64_insn_is_adr(insn) || aarch64_insn_is_adrp(insn);
}
-int aarch64_insn_read(void *addr, u32 *insnp);
-int aarch64_insn_write(void *addr, u32 insn);
enum aarch64_insn_encoding_class aarch64_get_insn_class(u32 insn);
bool aarch64_insn_uses_literal(u32 insn);
bool aarch64_insn_is_branch(u32 insn);
@@ -487,9 +485,6 @@ u32 aarch64_insn_gen_prefetch(enum aarch64_insn_register base,
s32 aarch64_get_branch_offset(u32 insn);
u32 aarch64_set_branch_offset(u32 insn, s32 offset);
-int aarch64_insn_patch_text_nosync(void *addr, u32 insn);
-int aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt);
-
s32 aarch64_insn_adrp_get_offset(u32 insn);
u32 aarch64_insn_adrp_set_offset(u32 insn, s32 offset);
diff --git a/arch/arm64/include/asm/patching.h b/arch/arm64/include/asm/patching.h
new file mode 100644
index 000000000000..6bf5adc56295
--- /dev/null
+++ b/arch/arm64/include/asm/patching.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASM_PATCHING_H
+#define __ASM_PATCHING_H
+
+#include <linux/types.h>
+
+int aarch64_insn_read(void *addr, u32 *insnp);
+int aarch64_insn_write(void *addr, u32 insn);
+
+int aarch64_insn_patch_text_nosync(void *addr, u32 insn);
+int aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt);
+
+#endif /* __ASM_PATCHING_H */
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index ed65576ce710..790af8c69338 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -17,7 +17,7 @@ obj-y := debug-monitors.o entry.o irq.o fpsimd.o \
return_address.o cpuinfo.o cpu_errata.o \
cpufeature.o alternative.o cacheinfo.o \
smp.o smp_spin_table.o topology.o smccc-call.o \
- syscall.o proton-pack.o idreg-override.o
+ syscall.o proton-pack.o idreg-override.o patching.o
targets += efi-entry.o
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index 86a5cf9bc19a..fd7993f0c9c4 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -15,6 +15,7 @@
#include <asm/debug-monitors.h>
#include <asm/ftrace.h>
#include <asm/insn.h>
+#include <asm/patching.h>
#ifdef CONFIG_DYNAMIC_FTRACE
/*
diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index 6c0de2f60ea9..952e7d6fe60e 100644
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -7,21 +7,14 @@
*/
#include <linux/bitops.h>
#include <linux/bug.h>
-#include <linux/compiler.h>
-#include <linux/kernel.h>
-#include <linux/mm.h>
-#include <linux/smp.h>
-#include <linux/spinlock.h>
-#include <linux/stop_machine.h>
+#include <linux/printk.h>
+#include <linux/sizes.h>
#include <linux/types.h>
-#include <linux/uaccess.h>
-#include <asm/cacheflush.h>
#include <asm/debug-monitors.h>
-#include <asm/fixmap.h>
+#include <asm/errno.h>
#include <asm/insn.h>
#include <asm/kprobes.h>
-#include <asm/sections.h>
#define AARCH64_INSN_SF_BIT BIT(31)
#define AARCH64_INSN_N_BIT BIT(22)
@@ -83,81 +76,6 @@ bool aarch64_insn_is_branch_imm(u32 insn)
aarch64_insn_is_bcond(insn));
}
-static DEFINE_RAW_SPINLOCK(patch_lock);
-
-static bool is_exit_text(unsigned long addr)
-{
- /* discarded with init text/data */
- return system_state < SYSTEM_RUNNING &&
- addr >= (unsigned long)__exittext_begin &&
- addr < (unsigned long)__exittext_end;
-}
-
-static bool is_image_text(unsigned long addr)
-{
- return core_kernel_text(addr) || is_exit_text(addr);
-}
-
-static void __kprobes *patch_map(void *addr, int fixmap)
-{
- unsigned long uintaddr = (uintptr_t) addr;
- bool image = is_image_text(uintaddr);
- struct page *page;
-
- if (image)
- page = phys_to_page(__pa_symbol(addr));
- else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
- page = vmalloc_to_page(addr);
- else
- return addr;
-
- BUG_ON(!page);
- return (void *)set_fixmap_offset(fixmap, page_to_phys(page) +
- (uintaddr & ~PAGE_MASK));
-}
-
-static void __kprobes patch_unmap(int fixmap)
-{
- clear_fixmap(fixmap);
-}
-/*
- * In ARMv8-A, A64 instructions have a fixed length of 32 bits and are always
- * little-endian.
- */
-int __kprobes aarch64_insn_read(void *addr, u32 *insnp)
-{
- int ret;
- __le32 val;
-
- ret = copy_from_kernel_nofault(&val, addr, AARCH64_INSN_SIZE);
- if (!ret)
- *insnp = le32_to_cpu(val);
-
- return ret;
-}
-
-static int __kprobes __aarch64_insn_write(void *addr, __le32 insn)
-{
- void *waddr = addr;
- unsigned long flags = 0;
- int ret;
-
- raw_spin_lock_irqsave(&patch_lock, flags);
- waddr = patch_map(addr, FIX_TEXT_POKE0);
-
- ret = copy_to_kernel_nofault(waddr, &insn, AARCH64_INSN_SIZE);
-
- patch_unmap(FIX_TEXT_POKE0);
- raw_spin_unlock_irqrestore(&patch_lock, flags);
-
- return ret;
-}
-
-int __kprobes aarch64_insn_write(void *addr, u32 insn)
-{
- return __aarch64_insn_write(addr, cpu_to_le32(insn));
-}
-
bool __kprobes aarch64_insn_uses_literal(u32 insn)
{
/* ldr/ldrsw (literal), prfm */
@@ -187,67 +105,6 @@ bool __kprobes aarch64_insn_is_branch(u32 insn)
aarch64_insn_is_bcond(insn);
}
-int __kprobes aarch64_insn_patch_text_nosync(void *addr, u32 insn)
-{
- u32 *tp = addr;
- int ret;
-
- /* A64 instructions must be word aligned */
- if ((uintptr_t)tp & 0x3)
- return -EINVAL;
-
- ret = aarch64_insn_write(tp, insn);
- if (ret == 0)
- __flush_icache_range((uintptr_t)tp,
- (uintptr_t)tp + AARCH64_INSN_SIZE);
-
- return ret;
-}
-
-struct aarch64_insn_patch {
- void **text_addrs;
- u32 *new_insns;
- int insn_cnt;
- atomic_t cpu_count;
-};
-
-static int __kprobes aarch64_insn_patch_text_cb(void *arg)
-{
- int i, ret = 0;
- struct aarch64_insn_patch *pp = arg;
-
- /* The first CPU becomes master */
- if (atomic_inc_return(&pp->cpu_count) == 1) {
- for (i = 0; ret == 0 && i < pp->insn_cnt; i++)
- ret = aarch64_insn_patch_text_nosync(pp->text_addrs[i],
- pp->new_insns[i]);
- /* Notify other processors with an additional increment. */
- atomic_inc(&pp->cpu_count);
- } else {
- while (atomic_read(&pp->cpu_count) <= num_online_cpus())
- cpu_relax();
- isb();
- }
-
- return ret;
-}
-
-int __kprobes aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt)
-{
- struct aarch64_insn_patch patch = {
- .text_addrs = addrs,
- .new_insns = insns,
- .insn_cnt = cnt,
- .cpu_count = ATOMIC_INIT(0),
- };
-
- if (cnt <= 0)
- return -EINVAL;
-
- return stop_machine_cpuslocked(aarch64_insn_patch_text_cb, &patch,
- cpu_online_mask);
-}
-
static int __kprobes aarch64_get_imm_shift_mask(enum aarch64_insn_imm_type type,
u32 *maskp, int *shiftp)
{
diff --git a/arch/arm64/kernel/jump_label.c b/arch/arm64/kernel/jump_label.c
index 9a8a0ae1e75f..fc98037e1220 100644
--- a/arch/arm64/kernel/jump_label.c
+++ b/arch/arm64/kernel/jump_label.c
@@ -8,6 +8,7 @@
#include <linux/kernel.h>
#include <linux/jump_label.h>
#include <asm/insn.h>
+#include <asm/patching.h>
void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type)
diff --git a/arch/arm64/kernel/patching.c b/arch/arm64/kernel/patching.c
new file mode 100644
index 000000000000..9d050e33901b
--- /dev/null
+++ b/arch/arm64/kernel/patching.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/stop_machine.h>
+#include <linux/uaccess.h>
+
+#include <asm/cacheflush.h>
+#include <asm/fixmap.h>
+#include <asm/kprobes.h>
+#include <asm/sections.h>
+
+static DEFINE_RAW_SPINLOCK(patch_lock);
+
+static bool is_exit_text(unsigned long addr)
+{
+ /* discarded with init text/data */
+ return system_state < SYSTEM_RUNNING &&
+ addr >= (unsigned long)__exittext_begin &&
+ addr < (unsigned long)__exittext_end;
+}
+
+static bool is_image_text(unsigned long addr)
+{
+ return core_kernel_text(addr) || is_exit_text(addr);
+}
+
+static void __kprobes *patch_map(void *addr, int fixmap)
+{
+ unsigned long uintaddr = (uintptr_t) addr;
+ bool image = is_image_text(uintaddr);
+ struct page *page;
+
+ if (image)
+ page = phys_to_page(__pa_symbol(addr));
+ else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
+ page = vmalloc_to_page(addr);
+ else
+ return addr;
+
+ BUG_ON(!page);
+ return (void *)set_fixmap_offset(fixmap, page_to_phys(page) +
+ (uintaddr & ~PAGE_MASK));
+}
+
+static void __kprobes patch_unmap(int fixmap)
+{
+ clear_fixmap(fixmap);
+}
+/*
+ * In ARMv8-A, A64 instructions have a fixed length of 32 bits and are always
+ * little-endian.
+ */
+int __kprobes aarch64_insn_read(void *addr, u32 *insnp)
+{
+ int ret;
+ __le32 val;
+
+ ret = copy_from_kernel_nofault(&val, addr, AARCH64_INSN_SIZE);
+ if (!ret)
+ *insnp = le32_to_cpu(val);
+
+ return ret;
+}
+
+static int __kprobes __aarch64_insn_write(void *addr, __le32 insn)
+{
+ void *waddr = addr;
+ unsigned long flags = 0;
+ int ret;
+
+ raw_spin_lock_irqsave(&patch_lock, flags);
+ waddr = patch_map(addr, FIX_TEXT_POKE0);
+
+ ret = copy_to_kernel_nofault(waddr, &insn, AARCH64_INSN_SIZE);
+
+ patch_unmap(FIX_TEXT_POKE0);
+ raw_spin_unlock_irqrestore(&patch_lock, flags);
+
+ return ret;
+}
+
+int __kprobes aarch64_insn_write(void *addr, u32 insn)
+{
+ return __aarch64_insn_write(addr, cpu_to_le32(insn));
+}
+
+int __kprobes aarch64_insn_patch_text_nosync(void *addr, u32 insn)
+{
+ u32 *tp = addr;
+ int ret;
+
+ /* A64 instructions must be word aligned */
+ if ((uintptr_t)tp & 0x3)
+ return -EINVAL;
+
+ ret = aarch64_insn_write(tp, insn);
+ if (ret == 0)
+ __flush_icache_range((uintptr_t)tp,
+ (uintptr_t)tp + AARCH64_INSN_SIZE);
+
+ return ret;
+}
+
+struct aarch64_insn_patch {
+ void **text_addrs;
+ u32 *new_insns;
+ int insn_cnt;
+ atomic_t cpu_count;
+};
+
+static int __kprobes aarch64_insn_patch_text_cb(void *arg)
+{
+ int i, ret = 0;
+ struct aarch64_insn_patch *pp = arg;
+
+ /* The first CPU becomes master */
+ if (atomic_inc_return(&pp->cpu_count) == 1) {
+ for (i = 0; ret == 0 && i < pp->insn_cnt; i++)
+ ret = aarch64_insn_patch_text_nosync(pp->text_addrs[i],
+ pp->new_insns[i]);
+ /* Notify other processors with an additional increment. */
+ atomic_inc(&pp->cpu_count);
+ } else {
+ while (atomic_read(&pp->cpu_count) <= num_online_cpus())
+ cpu_relax();
+ isb();
+ }
+
+ return ret;
+}
+
+int __kprobes aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt)
+{
+ struct aarch64_insn_patch patch = {
+ .text_addrs = addrs,
+ .new_insns = insns,
+ .insn_cnt = cnt,
+ .cpu_count = ATOMIC_INIT(0),
+ };
+
+ if (cnt <= 0)
+ return -EINVAL;
+
+ return stop_machine_cpuslocked(aarch64_insn_patch_text_cb, &patch,
+ cpu_online_mask);
+}
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index a05d34f0e82a..d7057e307bca 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -38,6 +38,7 @@
#include <asm/extable.h>
#include <asm/insn.h>
#include <asm/kprobes.h>
+#include <asm/patching.h>
#include <asm/traps.h>
#include <asm/smp.h>
#include <asm/stack_pointer.h>
--
2.25.4
More information about the linux-arm-kernel
mailing list