From 4f493a25f48e7e045b6d1a852f089f2a7268738e Mon Sep 17 00:00:00 2001 From: Konstantin Belousov Date: Tue, 21 May 2013 11:24:32 +0000 Subject: [PATCH] Fix the hardware watchpoints on SMP amd64. Load the updated %dr registers also on other CPUs, besides the CPU which happens to execute the ddb. The debugging registers are stored in the pcpu area, together with the command which is executed by the IPI stop handler upon resume. Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 1 week --- sys/amd64/amd64/db_trace.c | 79 ++++++++++++++++++++++++++---------- sys/amd64/amd64/mp_machdep.c | 5 +++ sys/amd64/include/md_var.h | 1 + sys/amd64/include/pcpu.h | 7 +++- 4 files changed, 69 insertions(+), 23 deletions(-) diff --git a/sys/amd64/amd64/db_trace.c b/sys/amd64/amd64/db_trace.c index 2c81f8765290..39297d9b2ed0 100644 --- a/sys/amd64/amd64/db_trace.c +++ b/sys/amd64/amd64/db_trace.c @@ -33,6 +33,7 @@ __FBSDID("$FreeBSD$"); #include #include #include +#include #include #include @@ -63,6 +64,8 @@ static db_varfcn_t db_frame; static db_varfcn_t db_rsp; static db_varfcn_t db_ss; +CTASSERT(sizeof(struct dbreg) == sizeof(((struct pcpu *)NULL)->pc_dbreg)); + /* * Machine register set. */ @@ -591,64 +594,82 @@ db_md_set_watchpoint(addr, size) db_expr_t addr; db_expr_t size; { - struct dbreg d; - int avail, i, wsize; + struct dbreg *d; + struct pcpu *pc; + int avail, c, cpu, i, wsize; - fill_dbregs(NULL, &d); + d = (struct dbreg *)PCPU_PTR(dbreg); + cpu = PCPU_GET(cpuid); + fill_dbregs(NULL, d); avail = 0; - for(i = 0; i < 4; i++) { - if (!DBREG_DR7_ENABLED(d.dr[7], i)) + for (i = 0; i < 4; i++) { + if (!DBREG_DR7_ENABLED(d->dr[7], i)) avail++; } if (avail * 8 < size) return (-1); - for (i = 0; i < 4 && (size > 0); i++) { - if (!DBREG_DR7_ENABLED(d.dr[7], i)) { + for (i = 0; i < 4 && size > 0; i++) { + if (!DBREG_DR7_ENABLED(d->dr[7], i)) { if (size >= 8 || (avail == 1 && size > 4)) wsize = 8; else if (size > 2) wsize = 4; else wsize = size; - amd64_set_watch(i, addr, wsize, - DBREG_DR7_WRONLY, &d); + amd64_set_watch(i, addr, wsize, DBREG_DR7_WRONLY, d); addr += wsize; size -= wsize; avail--; } } - set_dbregs(NULL, &d); + set_dbregs(NULL, d); + CPU_FOREACH(c) { + if (c == cpu) + continue; + pc = pcpu_find(c); + memcpy(pc->pc_dbreg, d, sizeof(*d)); + pc->pc_dbreg_cmd = PC_DBREG_CMD_LOAD; + } - return(0); + return (0); } - int db_md_clr_watchpoint(addr, size) db_expr_t addr; db_expr_t size; { - struct dbreg d; - int i; + struct dbreg *d; + struct pcpu *pc; + int i, c, cpu; - fill_dbregs(NULL, &d); + d = (struct dbreg *)PCPU_PTR(dbreg); + cpu = PCPU_GET(cpuid); + fill_dbregs(NULL, d); - for(i = 0; i < 4; i++) { - if (DBREG_DR7_ENABLED(d.dr[7], i)) { - if ((DBREG_DRX((&d), i) >= addr) && - (DBREG_DRX((&d), i) < addr+size)) - amd64_clr_watch(i, &d); + for (i = 0; i < 4; i++) { + if (DBREG_DR7_ENABLED(d->dr[7], i)) { + if (DBREG_DRX((d), i) >= addr && + DBREG_DRX((d), i) < addr + size) + amd64_clr_watch(i, d); } } - set_dbregs(NULL, &d); + set_dbregs(NULL, d); + CPU_FOREACH(c) { + if (c == cpu) + continue; + pc = pcpu_find(c); + memcpy(pc->pc_dbreg, d, sizeof(*d)); + pc->pc_dbreg_cmd = PC_DBREG_CMD_LOAD; + } - return(0); + return (0); } @@ -699,3 +720,17 @@ db_md_list_watchpoints() } db_printf("\n"); } + +void +amd64_db_resume_dbreg(void) +{ + struct dbreg *d; + + switch (PCPU_GET(dbreg_cmd)) { + case PC_DBREG_CMD_LOAD: + d = (struct dbreg *)PCPU_PTR(dbreg); + set_dbregs(NULL, d); + PCPU_SET(dbreg_cmd, PC_DBREG_CMD_NONE); + break; + } +} diff --git a/sys/amd64/amd64/mp_machdep.c b/sys/amd64/amd64/mp_machdep.c index 31dbb3f96fbf..5f4aacf9510a 100644 --- a/sys/amd64/amd64/mp_machdep.c +++ b/sys/amd64/amd64/mp_machdep.c @@ -28,6 +28,7 @@ __FBSDID("$FreeBSD$"); #include "opt_cpu.h" +#include "opt_ddb.h" #include "opt_kstack_pages.h" #include "opt_sched.h" #include "opt_smp.h" @@ -1396,6 +1397,10 @@ cpustop_handler(void) CPU_CLR_ATOMIC(cpu, &started_cpus); CPU_CLR_ATOMIC(cpu, &stopped_cpus); +#ifdef DDB + amd64_db_resume_dbreg(); +#endif + if (cpu == 0 && cpustop_restartfunc != NULL) { cpustop_restartfunc(); cpustop_restartfunc = NULL; diff --git a/sys/amd64/include/md_var.h b/sys/amd64/include/md_var.h index 5d7cb7469884..6ffcf633343d 100644 --- a/sys/amd64/include/md_var.h +++ b/sys/amd64/include/md_var.h @@ -117,5 +117,6 @@ void minidumpsys(struct dumperinfo *); struct savefpu *get_pcb_user_save_td(struct thread *td); struct savefpu *get_pcb_user_save_pcb(struct pcb *pcb); struct pcb *get_pcb_td(struct thread *td); +void amd64_db_resume_dbreg(void); #endif /* !_MACHINE_MD_VAR_H_ */ diff --git a/sys/amd64/include/pcpu.h b/sys/amd64/include/pcpu.h index bb7d33950535..ba4c61870797 100644 --- a/sys/amd64/include/pcpu.h +++ b/sys/amd64/include/pcpu.h @@ -78,9 +78,14 @@ struct system_segment_descriptor *pc_tss; \ u_int pc_cmci_mask /* MCx banks for CMCI */ \ PCPU_XEN_FIELDS; \ - char __pad[293] /* be divisor of PAGE_SIZE \ + uint64_t pc_dbreg[16]; /* ddb debugging regs */ \ + int pc_dbreg_cmd; /* ddb debugging reg cmd */ \ + char __pad[161] /* be divisor of PAGE_SIZE \ after cache alignment */ +#define PC_DBREG_CMD_NONE 0 +#define PC_DBREG_CMD_LOAD 1 + #ifdef _KERNEL #ifdef lint