On 10/29, Oleg Nesterov wrote: > > David. Perhaps we can avoid the new hook altogether? What if we do > the simple change below (it ignores powerpc) ? > > Then arm can add "unsigned long ixol[2]" into its arch_uprobe, and > arch_uprobe_analyze_insn() can initialize this member correctly. > > What do you think?
Seriouly, how about the patch below? In fact, given that you are going to reimplement set_swbp/orig_insn, the new member is not strictly needed (afaics). But it looks more clear this way, and we need s/MAX_UINSN_BYTES/sizeof()/ anyway. Oleg. --- Subject: [PATCH] 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 <[email protected]> --- arch/powerpc/include/asm/uprobes.h | 1 + arch/x86/include/asm/uprobes.h | 5 ++++- kernel/events/uprobes.c | 3 ++- 3 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/uprobes.h b/arch/powerpc/include/asm/uprobes.h index 2301602..541fd6f 100644 --- a/arch/powerpc/include/asm/uprobes.h +++ b/arch/powerpc/include/asm/uprobes.h @@ -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; }; }; diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 6e51979..2a24180 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -35,7 +35,10 @@ typedef u8 uprobe_opcode_t; struct arch_uprobe { u16 fixups; - u8 insn[MAX_UINSN_BYTES]; + union { + u8 insn[MAX_UINSN_BYTES]; + u8 ixol[MAX_UINSN_BYTES]; + }; #ifdef CONFIG_X86_64 unsigned long rip_rela_target_address; #endif diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index ad8e1bd..6aef5ad 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1256,7 +1256,8 @@ 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. -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
