Date: Wed, 3 Mar 2021 14:26:50 GMT From: Andrew Turner <andrew@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 28d945204ea1 - main - Handle functions that use a nop in the arm64 fbt Message-ID: <202103031426.123EQoM5082920@gitrepo.freebsd.org>
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The branch main has been updated by andrew: URL: https://cgit.FreeBSD.org/src/commit/?id=28d945204ea1014d7de6906af8470ed8b3311335 commit 28d945204ea1014d7de6906af8470ed8b3311335 Author: Andrew Turner <andrew@FreeBSD.org> AuthorDate: 2021-01-13 11:08:19 +0000 Commit: Andrew Turner <andrew@FreeBSD.org> CommitDate: 2021-03-03 14:18:03 +0000 Handle functions that use a nop in the arm64 fbt To trace leaf asm functions we can insert a single nop instruction as the first instruction in a function and trigger off this. Reviewed by: gnn Sponsored by: Innovate UK Differential Revision: https://reviews.freebsd.org/D28132 --- sys/arm64/include/asm.h | 8 +++- .../contrib/opensolaris/uts/common/sys/dtrace.h | 2 + sys/cddl/dev/dtrace/aarch64/dtrace_subr.c | 5 +++ sys/cddl/dev/fbt/aarch64/fbt_isa.c | 51 ++++++++++++++-------- 4 files changed, 46 insertions(+), 20 deletions(-) diff --git a/sys/arm64/include/asm.h b/sys/arm64/include/asm.h index 05e618500e59..32b79d256e80 100644 --- a/sys/arm64/include/asm.h +++ b/sys/arm64/include/asm.h @@ -38,9 +38,15 @@ #define _C_LABEL(x) x +#ifdef KDTRACE_HOOKS +#define DTRACE_NOP nop +#else +#define DTRACE_NOP +#endif + #define LENTRY(sym) \ .text; .align 2; .type sym,#function; sym: \ - .cfi_startproc + .cfi_startproc; DTRACE_NOP #define ENTRY(sym) \ .globl sym; LENTRY(sym) #define EENTRY(sym) \ diff --git a/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h b/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h index 2bedd01cf3e7..f15a971f12be 100644 --- a/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h +++ b/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h @@ -2466,6 +2466,8 @@ extern void dtrace_helpers_destroy(proc_t *); #define B_DATA_MASK 0x00ffffff #define B_INSTR 0x14000000 +#define NOP_INSTR 0xd503201f + #define RET_INSTR 0xd65f03c0 #define SUB_MASK 0xffc00000 diff --git a/sys/cddl/dev/dtrace/aarch64/dtrace_subr.c b/sys/cddl/dev/dtrace/aarch64/dtrace_subr.c index 9bf9f0798bb5..58d33511560b 100644 --- a/sys/cddl/dev/dtrace/aarch64/dtrace_subr.c +++ b/sys/cddl/dev/dtrace/aarch64/dtrace_subr.c @@ -314,6 +314,11 @@ dtrace_invop_start(struct trapframe *frame) return (0); } + if (invop == NOP_INSTR) { + frame->tf_elr += INSN_SIZE; + return (0); + } + if ((invop & B_MASK) == B_INSTR) { data = (invop & B_DATA_MASK); /* The data is the number of 4-byte words to change the pc */ diff --git a/sys/cddl/dev/fbt/aarch64/fbt_isa.c b/sys/cddl/dev/fbt/aarch64/fbt_isa.c index f15bc12291d3..12be95ea2217 100644 --- a/sys/cddl/dev/fbt/aarch64/fbt_isa.c +++ b/sys/cddl/dev/fbt/aarch64/fbt_isa.c @@ -110,28 +110,41 @@ fbt_provide_module_function(linker_file_t lf, int symindx, /* Look for stp (pre-indexed) operation */ found = false; - for (; instr < limit; instr++) { - /* Some functions start with "stp xt1, xt2, [xn, <const>]!" */ - if ((*instr & LDP_STP_MASK) == STP_64) { + /* + * If the first instruction is a nop it's a specially marked + * asm function. We only support a nop first as it's not a normal + * part of the function prologue. + */ + if (*instr == NOP_INSTR) + found = true; + if (!found) { + for (; instr < limit; instr++) { /* - * Assume any other store of this type means we - * are past the function prolog. + * Some functions start with + * "stp xt1, xt2, [xn, <const>]!" */ - if (((*instr >> ADDR_SHIFT) & ADDR_MASK) == 31) - found = true; - break; - } + 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; + } - /* - * Some functions start with a "sub sp, sp, <const>" - * Sometimes the compiler will have a sub instruction that - * is not of the above type so don't stop if we see one. - */ - if ((*instr & SUB_MASK) == SUB_INSTR && - ((*instr >> SUB_RD_SHIFT) & SUB_R_MASK) == 31 && - ((*instr >> SUB_RN_SHIFT) & SUB_R_MASK) == 31) { - found = true; - break; + /* + * Some functions start with a "sub sp, sp, <const>" + * Sometimes the compiler will have a sub instruction + * that is not of the above type so don't stop if we + * see one. + */ + if ((*instr & SUB_MASK) == SUB_INSTR && + ((*instr >> SUB_RD_SHIFT) & SUB_R_MASK) == 31 && + ((*instr >> SUB_RN_SHIFT) & SUB_R_MASK) == 31) { + found = true; + break; + } } }
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