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tile: define a macro ktext_writable_addr to get writable kernel text address

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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>
This commit is contained in:
Zhigang Lu 2015-09-30 09:53:47 +08:00 committed by Chris Metcalf
parent 9f9499ae8e
commit f419e6f63c
4 changed files with 14 additions and 4 deletions
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10
arch/tile/include/asm/page.h
View File

@ -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);

2
arch/tile/kernel/ftrace.c
View File

@ -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;

2
arch/tile/kernel/kgdb.c
View File

@ -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

4
arch/tile/kernel/kprobes.c
View File

@ -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)))