From 3c3a881b378f7538ffa8e11488dee934cf9cd4d0 Mon Sep 17 00:00:00 2001 From: patrick Date: Sun, 11 Feb 2018 21:04:13 +0000 Subject: [PATCH] Rework the DDB trace handling for armv7. By switching to clang the stack frame format has changed. Apparently AAPCS doesn't specify at all what a stack frame looks like. We end up with much simpler code, but also with a lot less information in the trace. ok kettenis@ --- sys/arch/arm/arm/db_trace.c | 76 ++++++------------------------------- 1 file changed, 12 insertions(+), 64 deletions(-) diff --git a/sys/arch/arm/arm/db_trace.c b/sys/arch/arm/arm/db_trace.c index 59c2ed65dab..4a88e58fca2 100644 --- a/sys/arch/arm/arm/db_trace.c +++ b/sys/arch/arm/arm/db_trace.c @@ -1,4 +1,4 @@ -/* $OpenBSD: db_trace.c,v 1.10 2017/01/24 00:58:55 mpi Exp $ */ +/* $OpenBSD: db_trace.c,v 1.11 2018/02/11 21:04:13 patrick Exp $ */ /* $NetBSD: db_trace.c,v 1.8 2003/01/17 22:28:48 thorpej Exp $ */ /* @@ -48,37 +48,11 @@ db_regs_t ddb_regs; #define INKERNEL(va) (((vaddr_t)(va)) >= VM_MIN_KERNEL_ADDRESS) /* - * APCS stack frames are awkward beasts, so I don't think even trying to use - * a structure to represent them is a good idea. - * - * Here's the diagram from the APCS. Increasing address is _up_ the page. - * - * save code pointer [fp] <- fp points to here - * return link value [fp, #-4] - * return sp value [fp, #-8] - * return fp value [fp, #-12] - * [saved v7 value] - * [saved v6 value] - * [saved v5 value] - * [saved v4 value] - * [saved v3 value] - * [saved v2 value] - * [saved v1 value] - * [saved a4 value] - * [saved a3 value] - * [saved a2 value] - * [saved a1 value] - * - * The save code pointer points twelve bytes beyond the start of the - * code sequence (usually a single STM) that created the stack frame. - * We have to disassemble it if we want to know which of the optional - * fields are actually present. + * return link value [fp, #+4] + * return fp value [fp] <- fp points to here */ - -#define FR_SCP (0) -#define FR_RLV (-1) -#define FR_RSP (-2) -#define FR_RFP (-3) +#define FR_RFP (0) +#define FR_RLV (+1) void db_stack_trace_print(db_expr_t addr, int have_addr, db_expr_t count, @@ -88,6 +62,7 @@ db_stack_trace_print(db_expr_t addr, int have_addr, db_expr_t count, char c, *cp = modif; boolean_t kernel_only = TRUE; boolean_t trace_thread = FALSE; + db_addr_t scp; int scp_offset; while ((c = *cp++) != 0) { @@ -97,9 +72,10 @@ db_stack_trace_print(db_expr_t addr, int have_addr, db_expr_t count, trace_thread = TRUE; } - if (!have_addr) + if (!have_addr) { frame = (u_int32_t *)(ddb_regs.tf_r11); - else { + scp = ddb_regs.tf_pc; + } else { if (trace_thread) { struct proc *p; struct user *u; @@ -112,6 +88,7 @@ db_stack_trace_print(db_expr_t addr, int have_addr, db_expr_t count, u = p->p_addr; frame = (u_int32_t *)(u->u_pcb.pcb_un.un_32.pcb32_r11); (*pr)("at %p\n", frame); + scp = u->u_pcb.pcb_un.un_32.pcb32_pc; } else frame = (u_int32_t *)(addr); } @@ -119,38 +96,9 @@ db_stack_trace_print(db_expr_t addr, int have_addr, db_expr_t count, scp_offset = -(get_pc_str_offset() >> 2); while (count-- && frame != NULL) { - db_addr_t scp; - u_int32_t savecode; - int r, n; - u_int32_t *rp; - const char *sep; - - /* - * In theory, the SCP isn't guaranteed to be in the function - * that generated the stack frame. We hope for the best. - */ - scp = frame[FR_SCP]; - db_printsym(scp, DB_STGY_PROC, pr); - (*pr)("\n\tscp=0x%08x rlv=0x%08x (", scp, frame[FR_RLV]); - db_printsym(frame[FR_RLV], DB_STGY_PROC, pr); - (*pr)(")\n\trsp=0x%08x rfp=0x%08x", - frame[FR_RSP], frame[FR_RFP]); - - savecode = ((u_int32_t *)scp)[scp_offset]; - if ((savecode & 0x0e100000) == 0x08000000) { - /* Looks like an STM */ - rp = frame - 4; - n = 0; - for (r = 10; r >= 0; r--) { - if (savecode & (1 << r)) { - sep = n++ % 4 == 0 ? "\n\t" : " "; - (*pr)("%sr%d=0x%08x", sep, r, *rp--); - } - } - } - - (*pr)("\n"); + (*pr)("\n\trlv=0x%08x rfp=0x%08x\n", frame[FR_RLV], frame[FR_RFP]); + scp = frame[FR_RLV]; /* * Switch to next frame up -- 2.20.1