[PATCH 0/3] kprobes: Misc bugfixes

[PATCH 0/3] kprobes: Misc bugfixes

[Masami Hiramatsu]

Hi,

Here are some bugfixes and cleanup for the kprobe architecture
dependent implementation. 2 of 3 are found by Jianhua Liu on
arm64 optprobe code. I found that the similar issue on ppc64
and arm32 implementation so fixed those. And last one was
reported by kernel test bot.

Thank you,

---

Masami Hiramatsu (3):
      ARM: kprobes: Count MAX_OPTINSN_SIZE in kprobe_opcode_t
      powerpc/kprobes: Fix alloc_optinsn_page() to use all area of optinsn_slot
      ia64: kprobes: Cleanup unused 'template' local variable


 arch/arm/include/asm/kprobes.h       |    3 +--
 arch/ia64/kernel/kprobes.c           |    3 ---
 arch/powerpc/include/asm/kprobes.h   |    6 ++++++
 arch/powerpc/kernel/optprobes.c      |   25 +++++++++++++++++++------
 arch/powerpc/kernel/optprobes_head.S |    5 ++---
 5 files changed, 28 insertions(+), 14 deletions(-)

--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>

[PATCH 1/3] ARM: kprobes: Count MAX_OPTINSN_SIZE in kprobe_opcode_t

[Masami Hiramatsu]

Count the MAX_OPTINSN_SIZE in 'kprobe_opcode_t' instead
of in byte. On arm, the sizeof(kprobe_opcode_t) is u32,
thus the current code consumes 4 times larger memory for
trampoline buffer.

Fixes: 0dc016dbd820 ("ARM: kprobes: enable OPTPROBES for ARM 32")
Reported-by: Jianhua Liu <jianhua.ljh@gmail.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
---
 arch/arm/include/asm/kprobes.h |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h
index e26a278d301a..092263a89102 100644
--- a/arch/arm/include/asm/kprobes.h
+++ b/arch/arm/include/asm/kprobes.h
@@ -56,8 +56,7 @@ extern __visible kprobe_opcode_t optprobe_template_restore_end[];
 
 #define MAX_OPTIMIZED_LENGTH	4
 #define MAX_OPTINSN_SIZE				\
-	((unsigned long)optprobe_template_end -	\
-	 (unsigned long)optprobe_template_entry)
+	(unsigned long)(optprobe_template_end - optprobe_template_entry)
 #define RELATIVEJUMP_SIZE	4
 
 struct arch_optimized_insn {

[PATCH 2/3] powerpc/kprobes: Fix alloc_optinsn_page() to use all area of optinsn_slot

[Masami Hiramatsu]

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:

[PATCH 3/3] ia64: kprobes: Cleanup unused 'template' local variable

[Masami Hiramatsu]

Remove unused 'template' local variable. This seems to be introduced
accidentally by a cleanup patch.

Fixes: a5403183d84d ("[PATCH] Kprobes IA64: arch_prepare_kprobes() cleanup")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
---
 arch/ia64/kernel/kprobes.c |    3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 1a7bab1c5d7c..31ed086d61c9 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -322,9 +322,6 @@ static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
 	       	unsigned long *kprobe_inst, uint *major_opcode)
 {
 	unsigned long kprobe_inst_p0, kprobe_inst_p1;
-	unsigned int template;
-
-	template = bundle->quad0.template;
 
 	switch (slot) {
 	  case 0: