Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [PATCH 2/3] powerpc/kprobes: Fix alloc_optinsn_page() to use all area of optinsn_slot | Date | Thu, 13 Jan 2022 23:55:45 +0900 |
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When the ppc64 uses 4K page size, most part of the optinsn_slot is not used because alloc_optinsn_page() is expected to return only one page-size memory. To use the remaining memories, make insn_page_in_use as array to manage page-sized slots and return corresponding memory address in the optinsn_slot.
Fixes: 51c9c0843993 ("powerpc/kprobes: Implement Optprobes") Reported-by: Jianhua Liu <jianhua.ljh@gmail.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Anju T <anju@linux.vnet.ibm.com> --- arch/powerpc/include/asm/kprobes.h | 6 ++++++ arch/powerpc/kernel/optprobes.c | 25 +++++++++++++++++++------ arch/powerpc/kernel/optprobes_head.S | 5 ++--- 3 files changed, 27 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/include/asm/kprobes.h b/arch/powerpc/include/asm/kprobes.h index bab364152b29..e7a5390effa8 100644 --- a/arch/powerpc/include/asm/kprobes.h +++ b/arch/powerpc/include/asm/kprobes.h @@ -4,6 +4,8 @@ #include <asm-generic/kprobes.h> +#ifndef __ASSEMBLY__ + #ifdef __KERNEL__ /* * Kernel Probes (KProbes) @@ -94,4 +96,8 @@ static inline int kprobe_handler(struct pt_regs *regs) { return 0; } static inline int kprobe_post_handler(struct pt_regs *regs) { return 0; } #endif /* CONFIG_KPROBES */ #endif /* __KERNEL__ */ +#endif /* __ASSEMBLY__ */ + +#define KPROBE_OPTINSN_SLOT_SIZE 65536 + #endif /* _ASM_POWERPC_KPROBES_H */ diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c index ce1903064031..eec2776ad2fd 100644 --- a/arch/powerpc/kernel/optprobes.c +++ b/arch/powerpc/kernel/optprobes.c @@ -25,19 +25,32 @@ #define TMPL_INSN_IDX (optprobe_template_insn - optprobe_template_entry) #define TMPL_END_IDX (optprobe_template_end - optprobe_template_entry) -static bool insn_page_in_use; +#define OPTINSN_SLOT_PAGES (KPROBE_OPTINSN_SLOT_SIZE / PAGE_SIZE) + +static bool insn_page_in_use[OPTINSN_SLOT_PAGES]; void *alloc_optinsn_page(void) { - if (insn_page_in_use) - return NULL; - insn_page_in_use = true; - return &optinsn_slot; + int i; + + for (i = 0; i < OPTINSN_SLOT_PAGES; i++) { + if (!insn_page_in_use[i]) { + insn_page_in_use[i] = true; + return (void *)((unsigned long)&optinsn_slot + PAGE_SIZE * i); + } + } + return NULL; } void free_optinsn_page(void *page) { - insn_page_in_use = false; + unsigned long idx = (unsigned long)page - (unsigned long)&optinsn_slot; + + WARN_ON_ONCE(idx & (PAGE_SIZE - 1)); + idx >>= PAGE_SHIFT; + if (WARN_ON_ONCE(idx >= OPTINSN_SLOT_PAGES)) + return; + insn_page_in_use[idx] = false; } /* diff --git a/arch/powerpc/kernel/optprobes_head.S b/arch/powerpc/kernel/optprobes_head.S index 19ea3312403c..bf2106836cc6 100644 --- a/arch/powerpc/kernel/optprobes_head.S +++ b/arch/powerpc/kernel/optprobes_head.S @@ -8,6 +8,7 @@ #include <asm/ppc_asm.h> #include <asm/ptrace.h> #include <asm/asm-offsets.h> +#include <asm/kprobes.h> #ifdef CONFIG_PPC64 #define SAVE_30GPRS(base) SAVE_10GPRS(2,base); SAVE_10GPRS(12,base); SAVE_10GPRS(22,base) @@ -19,8 +20,6 @@ #define TEMPLATE_FOR_IMM_LOAD_INSNS nop; nop; nop #endif -#define OPT_SLOT_SIZE 65536 - .balign 4 /* @@ -30,7 +29,7 @@ */ .global optinsn_slot optinsn_slot: - .space OPT_SLOT_SIZE + .space KPROBE_OPTINSN_SLOT_SIZE /* * Optprobe template:
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