arm64: Move patching utilities out of instruction encoding/decoding
authorJulien Thierry <jthierry@redhat.com>
Wed, 3 Mar 2021 17:05:29 +0000 (18:05 +0100)
committerWill Deacon <will@kernel.org>
Thu, 27 May 2021 16:37:25 +0000 (17:37 +0100)
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@redhat.com>
Link: https://lore.kernel.org/r/20210303170536.1838032-2-jthierry@redhat.com
[will: Include patching.h in insn.h to fix header mess; add __ASSEMBLY__ guards]
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
arch/arm64/include/asm/insn.h
arch/arm64/include/asm/patching.h [new file with mode: 0644]
arch/arm64/kernel/Makefile
arch/arm64/kernel/insn.c
arch/arm64/kernel/patching.c [new file with mode: 0644]

index 4ebb9c0..f08579e 100644 (file)
@@ -11,6 +11,7 @@
 #include <linux/types.h>
 
 #include <asm/alternative.h>
+#include <asm/patching.h>
 
 #ifndef __ASSEMBLY__
 /*
@@ -379,8 +380,6 @@ 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 +486,6 @@ 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 (file)
index 0000000..5ebab12
--- /dev/null
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef        __ASM_PATCHING_H
+#define        __ASM_PATCHING_H
+
+#include <linux/types.h>
+
+#ifndef __ASSEMBLY__
+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 /* __ASSEMBLY__ */
+
+#endif /* __ASM_PATCHING_H */
index 6cc9773..3693156 100644 (file)
@@ -22,7 +22,7 @@ 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
 
index 6c0de2f..952e7d6 100644 (file)
@@ -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/patching.c b/arch/arm64/kernel/patching.c
new file mode 100644 (file)
index 0000000..9d050e3
--- /dev/null
@@ -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);
+}