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authorZhigang Lu <zlu@ezchip.com>2015-09-30 04:53:47 +0300
committerChris Metcalf <cmetcalf@ezchip.com>2016-01-04 23:09:31 +0300
commitf419e6f63c5afea00d7c17ebf54f2d265f5c4d7e (patch)
treec9c49f97a3a3abd0c55fce3f41fe71ef0125d3af /arch/tile
parent9f9499ae8e6415cefc4fe0a96ad0e27864353c89 (diff)
downloadlinux-f419e6f63c5afea00d7c17ebf54f2d265f5c4d7e.tar.xz
tile: define a macro ktext_writable_addr to get writable kernel text address
It is used by kgdb, ftrace, kprobe and jump label, so we factor this out into a helper routine. Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com> Signed-off-by: Zhigang Lu <zlu@ezchip.com> Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Diffstat (limited to 'arch/tile')
-rw-r--r--arch/tile/include/asm/page.h10
-rw-r--r--arch/tile/kernel/ftrace.c2
-rw-r--r--arch/tile/kernel/kgdb.c2
-rw-r--r--arch/tile/kernel/kprobes.c4
4 files changed, 14 insertions, 4 deletions
diff --git a/arch/tile/include/asm/page.h b/arch/tile/include/asm/page.h
index a213a8d84a95..5cee2cbff2b1 100644
--- a/arch/tile/include/asm/page.h
+++ b/arch/tile/include/asm/page.h
@@ -319,6 +319,16 @@ static inline int pfn_valid(unsigned long pfn)
#define virt_to_page(kaddr) pfn_to_page(kaddr_to_pfn((void *)(kaddr)))
#define page_to_virt(page) pfn_to_kaddr(page_to_pfn(page))
+/*
+ * The kernel text is mapped at MEM_SV_START as read-only. To allow
+ * modifying kernel text, it is also mapped at PAGE_OFFSET as read-write.
+ * This macro converts a kernel address to its writable kernel text mapping,
+ * which is used to modify the text code on a running kernel by kgdb,
+ * ftrace, kprobe, jump label, etc.
+ */
+#define ktext_writable_addr(kaddr) \
+ ((unsigned long)(kaddr) - MEM_SV_START + PAGE_OFFSET)
+
struct mm_struct;
extern pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr);
extern pte_t *virt_to_kpte(unsigned long kaddr);
diff --git a/arch/tile/kernel/ftrace.c b/arch/tile/kernel/ftrace.c
index 0c0996175b1e..4180ccdf9cd0 100644
--- a/arch/tile/kernel/ftrace.c
+++ b/arch/tile/kernel/ftrace.c
@@ -117,7 +117,7 @@ static int ftrace_modify_code(unsigned long pc, unsigned long old,
return -EINVAL;
/* Operate on writable kernel text mapping. */
- pc_wr = pc - MEM_SV_START + PAGE_OFFSET;
+ pc_wr = ktext_writable_addr(pc);
if (probe_kernel_write((void *)pc_wr, &new, MCOUNT_INSN_SIZE))
return -EPERM;
diff --git a/arch/tile/kernel/kgdb.c b/arch/tile/kernel/kgdb.c
index ff5335ae050d..a506c2c28943 100644
--- a/arch/tile/kernel/kgdb.c
+++ b/arch/tile/kernel/kgdb.c
@@ -164,7 +164,7 @@ static unsigned long writable_address(unsigned long addr)
unsigned long ret = 0;
if (core_kernel_text(addr))
- ret = addr - MEM_SV_START + PAGE_OFFSET;
+ ret = ktext_writable_addr(addr);
else if (is_module_text_address(addr))
ret = addr;
else
diff --git a/arch/tile/kernel/kprobes.c b/arch/tile/kernel/kprobes.c
index f8a45c51e9e4..c68694bb1ad2 100644
--- a/arch/tile/kernel/kprobes.c
+++ b/arch/tile/kernel/kprobes.c
@@ -116,7 +116,7 @@ void __kprobes arch_arm_kprobe(struct kprobe *p)
unsigned long addr_wr;
/* Operate on writable kernel text mapping. */
- addr_wr = (unsigned long)p->addr - MEM_SV_START + PAGE_OFFSET;
+ addr_wr = ktext_writable_addr(p->addr);
if (probe_kernel_write((void *)addr_wr, &breakpoint_insn,
sizeof(breakpoint_insn)))
@@ -131,7 +131,7 @@ void __kprobes arch_disarm_kprobe(struct kprobe *kp)
unsigned long addr_wr;
/* Operate on writable kernel text mapping. */
- addr_wr = (unsigned long)kp->addr - MEM_SV_START + PAGE_OFFSET;
+ addr_wr = ktext_writable_addr(kp->addr);
if (probe_kernel_write((void *)addr_wr, &kp->opcode,
sizeof(kp->opcode)))