Author: gonzo
Date: Mon Mar 12 01:19:41 2012
New Revision: 232846
URL: http://svn.freebsd.org/changeset/base/232846
Log:
Implement pmc_save_user_callchain and pmc_save_kernel_callchain for MIPS
Modified:
head/sys/dev/hwpmc/hwpmc_mips.c
Modified: head/sys/dev/hwpmc/hwpmc_mips.c
==============================================================================
--- head/sys/dev/hwpmc/hwpmc_mips.c Mon Mar 12 01:15:58 2012
(r232845)
+++ head/sys/dev/hwpmc/hwpmc_mips.c Mon Mar 12 01:19:41 2012
(r232846)
@@ -34,6 +34,272 @@ __FBSDID("$FreeBSD$");
#include <machine/pmc_mdep.h>
#include <machine/md_var.h>
+#include <machine/mips_opcode.h>
+#include <machine/vmparam.h>
+
+#if defined(__mips_n64)
+# define MIPS_IS_VALID_KERNELADDR(reg) ((((reg) & 3) == 0) && \
+ ((vm_offset_t)(reg) >=
MIPS_XKPHYS_START))
+#else
+# define MIPS_IS_VALID_KERNELADDR(reg) ((((reg) & 3) == 0) && \
+ ((vm_offset_t)(reg) >=
MIPS_KSEG0_START))
+#endif
+
+/*
+ * We need some reasonable default to prevent backtrace code
+ * from wandering too far
+ */
+#define MAX_FUNCTION_SIZE 0x10000
+#define MAX_PROLOGUE_SIZE 0x100
+
+static int
+pmc_next_frame(register_t *pc, register_t *sp)
+{
+ InstFmt i;
+ uintptr_t va;
+ uint32_t instr, mask;
+ int more, stksize;
+ register_t ra = 0;
+
+ /* Jump here after a nonstandard (interrupt handler) frame */
+ stksize = 0;
+
+ /* check for bad SP: could foul up next frame */
+ if (!MIPS_IS_VALID_KERNELADDR(*sp)) {
+ goto error;
+ }
+
+ /* check for bad PC */
+ if (!MIPS_IS_VALID_KERNELADDR(*pc)) {
+ goto error;
+ }
+
+ /*
+ * Find the beginning of the current subroutine by scanning
+ * backwards from the current PC for the end of the previous
+ * subroutine.
+ */
+ va = *pc - sizeof(int);
+ while (1) {
+ instr = *((uint32_t *)va);
+
+ /* [d]addiu sp,sp,-X */
+ if (((instr & 0xffff8000) == 0x27bd8000)
+ || ((instr & 0xffff8000) == 0x67bd8000))
+ break;
+
+ /* jr ra */
+ if (instr == 0x03e00008) {
+ /* skip over branch-delay slot instruction */
+ va += 2 * sizeof(int);
+ break;
+ }
+
+ va -= sizeof(int);
+ }
+
+ /* skip over nulls which might separate .o files */
+ while ((instr = *((uint32_t *)va)) == 0)
+ va += sizeof(int);
+
+ /* scan forwards to find stack size and any saved registers */
+ stksize = 0;
+ more = 3;
+ mask = 0;
+ for (; more; va += sizeof(int),
+ more = (more == 3) ? 3 : more - 1) {
+ /* stop if hit our current position */
+ if (va >= *pc)
+ break;
+ instr = *((uint32_t *)va);
+ i.word = instr;
+ switch (i.JType.op) {
+ case OP_SPECIAL:
+ switch (i.RType.func) {
+ case OP_JR:
+ case OP_JALR:
+ more = 2; /* stop after next instruction
*/
+ break;
+
+ case OP_SYSCALL:
+ case OP_BREAK:
+ more = 1; /* stop now */
+ };
+ break;
+
+ case OP_BCOND:
+ case OP_J:
+ case OP_JAL:
+ case OP_BEQ:
+ case OP_BNE:
+ case OP_BLEZ:
+ case OP_BGTZ:
+ more = 2; /* stop after next instruction */
+ break;
+
+ case OP_COP0:
+ case OP_COP1:
+ case OP_COP2:
+ case OP_COP3:
+ switch (i.RType.rs) {
+ case OP_BCx:
+ case OP_BCy:
+ more = 2; /* stop after next instruction
*/
+ };
+ break;
+
+ case OP_SW:
+ case OP_SD:
+ /* look for saved registers on the stack */
+ if (i.IType.rs != 29)
+ break;
+ /* only restore the first one */
+ if (mask & (1 << i.IType.rt))
+ break;
+ mask |= (1 << i.IType.rt);
+ if (i.IType.rt == 31)
+ ra = *((register_t *)(*sp +
(short)i.IType.imm));
+ break;
+
+ case OP_ADDI:
+ case OP_ADDIU:
+ case OP_DADDI:
+ case OP_DADDIU:
+ /* look for stack pointer adjustment */
+ if (i.IType.rs != 29 || i.IType.rt != 29)
+ break;
+ stksize = -((short)i.IType.imm);
+ }
+ }
+
+ if (!MIPS_IS_VALID_KERNELADDR(ra))
+ return (-1);
+
+ *pc = ra;
+ *sp += stksize;
+
+ return (0);
+
+error:
+ return (-1);
+}
+
+static int
+pmc_next_uframe(register_t *pc, register_t *sp, register_t *ra)
+{
+ int offset, registers_on_stack;
+ uint32_t opcode, mask;
+ register_t function_start;
+ int stksize;
+ InstFmt i;
+
+ registers_on_stack = 0;
+ mask = 0;
+ function_start = 0;
+ offset = 0;
+ stksize = 0;
+
+ while (offset < MAX_FUNCTION_SIZE) {
+ opcode = fuword32((void *)(*pc - offset));
+
+ /* [d]addiu sp, sp, -X*/
+ if (((opcode & 0xffff8000) == 0x27bd8000)
+ || ((opcode & 0xffff8000) == 0x67bd8000)) {
+ function_start = *pc - offset;
+ registers_on_stack = 1;
+ break;
+ }
+
+ /* lui gp, X */
+ if ((opcode & 0xffff8000) == 0x3c1c0000) {
+ /*
+ * Function might start with this instruction
+ * Keep an eye on "jr ra" and sp correction
+ * with positive value further on
+ */
+ function_start = *pc - offset;
+ }
+
+ if (function_start) {
+ /*
+ * Stop looking further. Possible end of
+ * function instruction: it means there is no
+ * stack modifications, sp is unchanged
+ */
+
+ /* [d]addiu sp,sp,X */
+ if (((opcode & 0xffff8000) == 0x27bd0000)
+ || ((opcode & 0xffff8000) == 0x67bd0000))
+ break;
+
+ if (opcode == 0x03e00008)
+ break;
+ }
+
+ offset += sizeof(int);
+ }
+
+ if (!function_start)
+ return (-1);
+
+ if (registers_on_stack) {
+ offset = 0;
+ while ((offset < MAX_PROLOGUE_SIZE)
+ && ((function_start + offset) < *pc)) {
+ i.word = fuword32((void *)(function_start + offset));
+ switch (i.JType.op) {
+ case OP_SW:
+ /* look for saved registers on the stack */
+ if (i.IType.rs != 29)
+ break;
+ /* only restore the first one */
+ if (mask & (1 << i.IType.rt))
+ break;
+ mask |= (1 << i.IType.rt);
+ if (i.IType.rt == 31)
+ *ra = fuword32((void *)(*sp +
(short)i.IType.imm));
+ break;
+
+#if defined(__mips_n64)
+ case OP_SD:
+ /* look for saved registers on the stack */
+ if (i.IType.rs != 29)
+ break;
+ /* only restore the first one */
+ if (mask & (1 << i.IType.rt))
+ break;
+ mask |= (1 << i.IType.rt);
+ /* ra */
+ if (i.IType.rt == 31)
+ *ra = fuword64((void *)(*sp +
(short)i.IType.imm));
+ break;
+#endif
+
+ case OP_ADDI:
+ case OP_ADDIU:
+ case OP_DADDI:
+ case OP_DADDIU:
+ /* look for stack pointer adjustment */
+ if (i.IType.rs != 29 || i.IType.rt != 29)
+ break;
+ stksize = -((short)i.IType.imm);
+ }
+
+ offset += sizeof(int);
+ }
+ }
+
+ /*
+ * We reached the end of backtrace
+ */
+ if (*pc == *ra)
+ return (-1);
+
+ *pc = *ra;
+ *sp += stksize;
+
+ return (0);
+}
struct pmc_mdep *
pmc_md_initialize()
@@ -55,21 +321,53 @@ pmc_md_finalize(struct pmc_mdep *md)
}
int
-pmc_save_kernel_callchain(uintptr_t *cc, int maxsamples,
+pmc_save_kernel_callchain(uintptr_t *cc, int nframes,
struct trapframe *tf)
{
- (void) cc;
- (void) maxsamples;
- (void) tf;
- return (0);
+ register_t pc, ra, sp;
+ int frames = 0;
+
+ pc = (uint64_t)tf->pc;
+ sp = (uint64_t)tf->sp;
+ ra = (uint64_t)tf->ra;
+
+ /*
+ * Unwind, and unwind, and unwind
+ */
+ while (1) {
+ cc[frames++] = pc;
+ if (frames >= nframes)
+ break;
+
+ if (pmc_next_frame(&pc, &sp) < 0)
+ break;
+ }
+
+ return (frames);
}
int
-pmc_save_user_callchain(uintptr_t *cc, int maxsamples,
+pmc_save_user_callchain(uintptr_t *cc, int nframes,
struct trapframe *tf)
{
- (void) cc;
- (void) maxsamples;
- (void) tf;
- return (0);
+ register_t pc, ra, sp;
+ int frames = 0;
+
+ pc = (uint64_t)tf->pc;
+ sp = (uint64_t)tf->sp;
+ ra = (uint64_t)tf->ra;
+
+ /*
+ * Unwind, and unwind, and unwind
+ */
+ while (1) {
+ cc[frames++] = pc;
+ if (frames >= nframes)
+ break;
+
+ if (pmc_next_uframe(&pc, &sp, &ra) < 0)
+ break;
+ }
+
+ return (frames);
}
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