6.6-stable review patch. If anyone has any objections, please let me know.
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From: Hui Li lihui@loongson.cn
commit f63a47b34b140ed1ca39d7e4bd4f1cdc617fc316 upstream.
In the current code, when debugging the following code using gdb, "invalid argument ..." message will be displayed.
lihui@bogon:~$ cat test.c #include <stdio.h> int a = 0; int main() { a = 1; return 0; } lihui@bogon:~$ gcc -g test.c -o test lihui@bogon:~$ gdb test ... (gdb) watch a Hardware watchpoint 1: a (gdb) r ... Invalid argument setting hardware debug registers
There are mainly two types of issues.
1. Some incorrect judgment condition existed in user_watch_state argument parsing, causing -EINVAL to be returned.
When setting up a watchpoint, gdb uses the ptrace interface, ptrace(PTRACE_SETREGSET, tid, NT_LOONGARCH_HW_WATCH, (void *) &iov)). Register values in user_watch_state as follows:
addr[0] = 0x0, mask[0] = 0x0, ctrl[0] = 0x0 addr[1] = 0x0, mask[1] = 0x0, ctrl[1] = 0x0 addr[2] = 0x0, mask[2] = 0x0, ctrl[2] = 0x0 addr[3] = 0x0, mask[3] = 0x0, ctrl[3] = 0x0 addr[4] = 0x0, mask[4] = 0x0, ctrl[4] = 0x0 addr[5] = 0x0, mask[5] = 0x0, ctrl[5] = 0x0 addr[6] = 0x0, mask[6] = 0x0, ctrl[6] = 0x0 addr[7] = 0x12000803c, mask[7] = 0x0, ctrl[7] = 0x610
In arch_bp_generic_fields(), return -EINVAL when ctrl.len is LOONGARCH_BREAKPOINT_LEN_8(0b00). So delete the incorrect judgment here.
In ptrace_hbp_fill_attr_ctrl(), when note_type is NT_LOONGARCH_HW_WATCH and ctrl[0] == 0x0, if ((type & HW_BREAKPOINT_RW) != type) will return -EINVAL. Here ctrl.type should be set based on note_type, and unnecessary judgments can be removed.
2. The watchpoint argument was not set correctly due to unnecessary offset and alignment_mask.
Modify ptrace_hbp_fill_attr_ctrl() and hw_breakpoint_arch_parse(), which ensure the watchpont argument is set correctly.
All changes according to the LoongArch Reference Manual: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#co...
Cc: stable@vger.kernel.org Signed-off-by: Hui Li lihui@loongson.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/loongarch/include/asm/hw_breakpoint.h | 2 - arch/loongarch/kernel/hw_breakpoint.c | 19 ++++------------- arch/loongarch/kernel/ptrace.c | 32 +++++++++++++---------------- 3 files changed, 21 insertions(+), 32 deletions(-)
--- a/arch/loongarch/include/asm/hw_breakpoint.h +++ b/arch/loongarch/include/asm/hw_breakpoint.h @@ -101,7 +101,7 @@ struct perf_event; struct perf_event_attr;
extern int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl, - int *gen_len, int *gen_type, int *offset); + int *gen_len, int *gen_type); extern int arch_check_bp_in_kernelspace(struct arch_hw_breakpoint *hw); extern int hw_breakpoint_arch_parse(struct perf_event *bp, const struct perf_event_attr *attr, --- a/arch/loongarch/kernel/hw_breakpoint.c +++ b/arch/loongarch/kernel/hw_breakpoint.c @@ -283,7 +283,7 @@ int arch_check_bp_in_kernelspace(struct * to generic breakpoint descriptions. */ int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl, - int *gen_len, int *gen_type, int *offset) + int *gen_len, int *gen_type) { /* Type */ switch (ctrl.type) { @@ -303,11 +303,6 @@ int arch_bp_generic_fields(struct arch_h return -EINVAL; }
- if (!ctrl.len) - return -EINVAL; - - *offset = __ffs(ctrl.len); - /* Len */ switch (ctrl.len) { case LOONGARCH_BREAKPOINT_LEN_1: @@ -386,21 +381,17 @@ int hw_breakpoint_arch_parse(struct perf struct arch_hw_breakpoint *hw) { int ret; - u64 alignment_mask, offset; + u64 alignment_mask;
/* Build the arch_hw_breakpoint. */ ret = arch_build_bp_info(bp, attr, hw); if (ret) return ret;
- if (hw->ctrl.type != LOONGARCH_BREAKPOINT_EXECUTE) - alignment_mask = 0x7; - else + if (hw->ctrl.type == LOONGARCH_BREAKPOINT_EXECUTE) { alignment_mask = 0x3; - offset = hw->address & alignment_mask; - - hw->address &= ~alignment_mask; - hw->ctrl.len <<= offset; + hw->address &= ~alignment_mask; + }
return 0; } --- a/arch/loongarch/kernel/ptrace.c +++ b/arch/loongarch/kernel/ptrace.c @@ -494,28 +494,14 @@ static int ptrace_hbp_fill_attr_ctrl(uns struct arch_hw_breakpoint_ctrl ctrl, struct perf_event_attr *attr) { - int err, len, type, offset; + int err, len, type;
- err = arch_bp_generic_fields(ctrl, &len, &type, &offset); + err = arch_bp_generic_fields(ctrl, &len, &type); if (err) return err;
- switch (note_type) { - case NT_LOONGARCH_HW_BREAK: - if ((type & HW_BREAKPOINT_X) != type) - return -EINVAL; - break; - case NT_LOONGARCH_HW_WATCH: - if ((type & HW_BREAKPOINT_RW) != type) - return -EINVAL; - break; - default: - return -EINVAL; - } - attr->bp_len = len; attr->bp_type = type; - attr->bp_addr += offset;
return 0; } @@ -609,7 +595,19 @@ static int ptrace_hbp_set_ctrl(unsigned return PTR_ERR(bp);
attr = bp->attr; - decode_ctrl_reg(uctrl, &ctrl); + + switch (note_type) { + case NT_LOONGARCH_HW_BREAK: + ctrl.type = LOONGARCH_BREAKPOINT_EXECUTE; + ctrl.len = LOONGARCH_BREAKPOINT_LEN_4; + break; + case NT_LOONGARCH_HW_WATCH: + decode_ctrl_reg(uctrl, &ctrl); + break; + default: + return -EINVAL; + } + err = ptrace_hbp_fill_attr_ctrl(note_type, ctrl, &attr); if (err) return err;