Author: wma Date: Wed Apr 6 05:13:36 2016 New Revision: 297611 URL: https://svnweb.freebsd.org/changeset/base/297611
Log: Implement dtrace_getupcstack in ARM64 Allow using DTRACE for performance analysis of userspace applications - the function call stack can be captured. This is almost an exact copy of AMD64 solution. Obtained from: Semihalf Sponsored by: Cavium Reviewed by: emaste, gnn, jhibbits Differential Revision: https://reviews.freebsd.org/D5779 Modified: head/sys/arm64/include/frame.h head/sys/cddl/dev/dtrace/aarch64/dtrace_isa.c Modified: head/sys/arm64/include/frame.h ============================================================================== --- head/sys/arm64/include/frame.h Wed Apr 6 04:58:20 2016 (r297610) +++ head/sys/arm64/include/frame.h Wed Apr 6 05:13:36 2016 (r297611) @@ -49,6 +49,11 @@ struct trapframe { uint64_t tf_x[30]; }; +struct arm64_frame { + struct arm64_frame *f_frame; + u_long f_retaddr; +}; + /* * Signal frame, pushedonto the user stack */ Modified: head/sys/cddl/dev/dtrace/aarch64/dtrace_isa.c ============================================================================== --- head/sys/cddl/dev/dtrace/aarch64/dtrace_isa.c Wed Apr 6 04:58:20 2016 (r297610) +++ head/sys/cddl/dev/dtrace/aarch64/dtrace_isa.c Wed Apr 6 05:13:36 2016 (r297611) @@ -57,6 +57,7 @@ */ #define MAX_FUNCTION_SIZE 0x10000 #define MAX_PROLOGUE_SIZE 0x100 +#define MAX_USTACK_DEPTH 2048 uint8_t dtrace_fuword8_nocheck(void *); uint16_t dtrace_fuword16_nocheck(void *); @@ -111,11 +112,127 @@ dtrace_getpcstack(pc_t *pcstack, int pcs } } +static int +dtrace_getustack_common(uint64_t *pcstack, int pcstack_limit, uintptr_t pc, + uintptr_t fp) +{ + volatile uint16_t *flags = + (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags; + int ret = 0; + uintptr_t oldfp; + + ASSERT(pcstack == NULL || pcstack_limit > 0); + + while (pc != 0) { + /* + * We limit the number of times we can go around this + * loop to account for a circular stack. + */ + if (ret++ >= MAX_USTACK_DEPTH) { + *flags |= CPU_DTRACE_BADSTACK; + cpu_core[curcpu].cpuc_dtrace_illval = fp; + break; + } + + if (pcstack != NULL) { + *pcstack++ = (uint64_t)pc; + pcstack_limit--; + if (pcstack_limit <= 0) + break; + } + + if (fp == 0) + break; + + pc = dtrace_fuword64((void *)(fp + + offsetof(struct arm64_frame, f_retaddr))); + fp = dtrace_fuword64((void *)fp); + + if (fp == oldfp) { + *flags |= CPU_DTRACE_BADSTACK; + cpu_core[curcpu].cpuc_dtrace_illval = fp; + break; + } + + /* + * ARM64TODO: + * This workaround might not be necessary. It needs to be + * revised and removed from all architectures if found + * unwanted. Leaving the original x86 comment for reference. + * + * This is totally bogus: if we faulted, we're going to clear + * the fault and break. This is to deal with the apparently + * broken Java stacks on x86. + */ + if (*flags & CPU_DTRACE_FAULT) { + *flags &= ~CPU_DTRACE_FAULT; + break; + } + } + + return (ret); +} + void dtrace_getupcstack(uint64_t *pcstack, int pcstack_limit) { + proc_t *p = curproc; + struct trapframe *tf; + uintptr_t pc, sp, fp; + volatile uint16_t *flags = + (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags; + int n; + + if (*flags & CPU_DTRACE_FAULT) + return; + + if (pcstack_limit <= 0) + return; + + /* + * If there's no user context we still need to zero the stack. + */ + if (p == NULL || (tf = curthread->td_frame) == NULL) + goto zero; + + *pcstack++ = (uint64_t)p->p_pid; + pcstack_limit--; + + if (pcstack_limit <= 0) + return; + + pc = tf->tf_elr; + sp = tf->tf_sp; + fp = tf->tf_x[29]; - printf("IMPLEMENT ME: %s\n", __func__); + if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) { + /* + * In an entry probe. The frame pointer has not yet been + * pushed (that happens in the function prologue). The + * best approach is to add the current pc as a missing top + * of stack and back the pc up to the caller, which is stored + * at the current stack pointer address since the call + * instruction puts it there right before the branch. + */ + + *pcstack++ = (uint64_t)pc; + pcstack_limit--; + if (pcstack_limit <= 0) + return; + + pc = tf->tf_lr; + } + + n = dtrace_getustack_common(pcstack, pcstack_limit, pc, fp); + ASSERT(n >= 0); + ASSERT(n <= pcstack_limit); + + pcstack += n; + pcstack_limit -= n; + +zero: + while (pcstack_limit-- > 0) + *pcstack++ = 0; } int _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
