[PATCH v6 1/8] powerpc/watchpoint: Fix quarword instruction handling on p10 predecessors
From: Ravi Bangoria <hidden>
Date: 2020-09-02 04:30:27
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
On p10 predecessors, watchpoint with quarword access is compared at
quardword length. If the watch range is doubleword or less than that
in a first half of quarword aligned 16 bytes, and if there is any
unaligned quadword access which will access only the 2nd half, the
handler should consider it as extraneous and emulate/single-step it
before continuing.
Reported-by: Pedro Miraglia Franco de Carvalho <redacted>
Fixes: 74c6881019b7 ("powerpc/watchpoint: Prepare handler to handle more than one watchpoint")
Signed-off-by: Ravi Bangoria <redacted>
---
arch/powerpc/include/asm/hw_breakpoint.h | 1 +
arch/powerpc/kernel/hw_breakpoint.c | 12 ++++++++++--
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
index db206a7f38e2..9b68eafebf43 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h@@ -42,6 +42,7 @@ struct arch_hw_breakpoint { #else #define HW_BREAKPOINT_SIZE 0x8 #endif +#define HW_BREAKPOINT_SIZE_QUADWORD 0x10 #define DABR_MAX_LEN 8 #define DAWR_MAX_LEN 512
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 1f4a1efa0074..9f7df1c37233 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c@@ -520,9 +520,17 @@ static bool ea_hw_range_overlaps(unsigned long ea, int size, struct arch_hw_breakpoint *info) { unsigned long hw_start_addr, hw_end_addr; + unsigned long align_size = HW_BREAKPOINT_SIZE; - hw_start_addr = ALIGN_DOWN(info->address, HW_BREAKPOINT_SIZE); - hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE); + /* + * On p10 predecessors, quadword is handle differently then + * other instructions. + */ + if (!cpu_has_feature(CPU_FTR_ARCH_31) && size == 16) + align_size = HW_BREAKPOINT_SIZE_QUADWORD; + + hw_start_addr = ALIGN_DOWN(info->address, align_size); + hw_end_addr = ALIGN(info->address + info->len, align_size); return ((ea < hw_end_addr) && (ea + size > hw_start_addr)); }
--
2.26.2