The branch main has been updated by andrew: URL: https://cgit.FreeBSD.org/src/commit/?id=d0df1a2d54dcba438018f4be1d8bbaeac7e49d92
commit d0df1a2d54dcba438018f4be1d8bbaeac7e49d92 Author: Andrew Turner <[email protected]> AuthorDate: 2021-01-12 11:37:06 +0000 Commit: Andrew Turner <[email protected]> CommitDate: 2021-01-12 12:42:23 +0000 Only allow a store through sp in the arm64 fbt When searching for an instruction to patch out in the arm64 function boundary trace we search for a store pair with a write back. This instruction is commonly used to store two registers to the stack and update the stack pointer to hold space for more. This works in many cases, however not all functions use this, e.g. when the stack frame is too large. In these cases we may find another instruction of the same type that doesn't store through the stack pointer. Filter these instructions out and assume if we see one we are past the function prologue. Reported by: rwatson Sponsored by: Innovate UK --- sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h | 4 +++- sys/cddl/dev/fbt/aarch64/fbt_isa.c | 16 +++++++++++++--- 2 files changed, 16 insertions(+), 4 deletions(-) diff --git a/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h b/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h index 31c5983270ca..922c1a9bba9b 100644 --- a/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h +++ b/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h @@ -2479,11 +2479,13 @@ extern void dtrace_helpers_destroy(proc_t *); #define ARG1_MASK 0x1f #define ARG2_SHIFT 10 #define ARG2_MASK 0x1f +#define ADDR_SHIFT 5 +#define ADDR_MASK 0x1f #define OFFSET_SHIFT 15 #define OFFSET_SIZE 7 #define OFFSET_MASK ((1 << OFFSET_SIZE) - 1) -#define DTRACE_INVOP_PUSHM 1 +#define DTRACE_INVOP_STP 1 #define DTRACE_INVOP_RET 2 #define DTRACE_INVOP_B 3 diff --git a/sys/cddl/dev/fbt/aarch64/fbt_isa.c b/sys/cddl/dev/fbt/aarch64/fbt_isa.c index 3c5070785614..9235af1a4c65 100644 --- a/sys/cddl/dev/fbt/aarch64/fbt_isa.c +++ b/sys/cddl/dev/fbt/aarch64/fbt_isa.c @@ -87,6 +87,7 @@ fbt_provide_module_function(linker_file_t lf, int symindx, uint32_t *instr, *limit; const char *name; char *modname; + bool found; int offs; modname = opaque; @@ -108,12 +109,21 @@ fbt_provide_module_function(linker_file_t lf, int symindx, limit = (uint32_t *)(symval->value + symval->size); /* Look for stp (pre-indexed) operation */ + found = false; for (; instr < limit; instr++) { - if ((*instr & LDP_STP_MASK) == STP_64) + /* Some functions start with "stp xt1, xt2, [xn, <const>]!" */ + if ((*instr & LDP_STP_MASK) == STP_64) { + /* + * Assume any other store of this type means we + * are past the function prolog. + */ + if (((*instr >> ADDR_SHIFT) & ADDR_MASK) == 31) + found = true; break; + } } - if (instr >= limit) + if (!found) return (0); fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO); @@ -125,7 +135,7 @@ fbt_provide_module_function(linker_file_t lf, int symindx, fbt->fbtp_loadcnt = lf->loadcnt; fbt->fbtp_savedval = *instr; fbt->fbtp_patchval = FBT_PATCHVAL; - fbt->fbtp_rval = DTRACE_INVOP_PUSHM; + fbt->fbtp_rval = DTRACE_INVOP_STP; fbt->fbtp_symindx = symindx; fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)]; _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-main To unsubscribe, send any mail to "[email protected]"
