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Commit 8a8de66c authored Nov 04, 2013 by Oleg Nesterov

uprobes: Introduce arch_uprobe->ixol



Currently xol_get_insn_slot() assumes that we should simply copy
arch_uprobe->insn[] which is (ignoring arch_uprobe_analyze_insn)
just the copy of the original insn.

This is not true for arm which needs to create another insn to
execute it out-of-line.

So this patch simply adds the new member, ->ixol into the union.
This doesn't make any difference for x86 and powerpc, but arm
can divorce insn/ixol and initialize the correct xol insn in
arch_uprobe_analyze_insn().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>

parent 736e89d9

arch/powerpc/include/asm/uprobes.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -37,6 +37,7 @@ typedef ppc_opcode_t uprobe_opcode_t;
		struct arch_uprobe {
		union {
		u8 insn[MAX_UINSN_BYTES];
		u8 ixol[MAX_UINSN_BYTES];
		u32 ainsn;
		};
		};

arch/x86/include/asm/uprobes.h

+4 −1

Original line number	Diff line number	Diff line
		@@ -35,7 +35,10 @@ typedef u8 uprobe_opcode_t;

		struct arch_uprobe {
		u16 fixups;
		union {
		u8 insn[MAX_UINSN_BYTES];
		u8 ixol[MAX_UINSN_BYTES];
		};
		#ifdef CONFIG_X86_64
		unsigned long rip_rela_target_address;
		#endif

kernel/events/uprobes.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1264,7 +1264,8 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
		return 0;

		/* Initialize the slot */
		copy_to_page(area->page, xol_vaddr, uprobe->arch.insn, MAX_UINSN_BYTES);
		copy_to_page(area->page, xol_vaddr,
		uprobe->arch.ixol, sizeof(uprobe->arch.ixol));
		/*
		* We probably need flush_icache_user_range() but it needs vma.
		* This should work on supported architectures too.