freebsd-dev/sys/arm64/include/asm.h
Andrew Turner 28d945204e 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
2021-03-03 14:18:03 +00:00

116 lines
3.6 KiB
C

/*-
* Copyright (c) 2014 Andrew Turner
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _MACHINE_ASM_H_
#define _MACHINE_ASM_H_
#undef __FBSDID
#if !defined(lint) && !defined(STRIP_FBSDID)
#define __FBSDID(s) .ident s
#else
#define __FBSDID(s) /* nothing */
#endif
#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; DTRACE_NOP
#define ENTRY(sym) \
.globl sym; LENTRY(sym)
#define EENTRY(sym) \
.globl sym; sym:
#define LEND(sym) .ltorg; .cfi_endproc; .size sym, . - sym
#define END(sym) LEND(sym)
#define EEND(sym)
#define WEAK_REFERENCE(sym, alias) \
.weak alias; \
.set alias,sym
#define UINT64_C(x) (x)
#if defined(PIC)
#define PIC_SYM(x,y) x ## @ ## y
#else
#define PIC_SYM(x,y) x
#endif
/* Alias for link register x30 */
#define lr x30
/*
* Sets the trap fault handler. The exception handler will return to the
* address in the handler register on a data abort or the xzr register to
* clear the handler. The tmp parameter should be a register able to hold
* the temporary data.
*/
#define SET_FAULT_HANDLER(handler, tmp) \
ldr tmp, [x18, #PC_CURTHREAD]; /* Load curthread */ \
ldr tmp, [tmp, #TD_PCB]; /* Load the pcb */ \
str handler, [tmp, #PCB_ONFAULT] /* Set the handler */
#define ENTER_USER_ACCESS(reg, tmp) \
ldr tmp, =has_pan; /* Get the addr of has_pan */ \
ldr reg, [tmp]; /* Read it */ \
cbz reg, 997f; /* If no PAN skip */ \
.inst 0xd500409f | (0 << 8); /* Clear PAN */ \
997:
#define EXIT_USER_ACCESS(reg) \
cbz reg, 998f; /* If no PAN skip */ \
.inst 0xd500409f | (1 << 8); /* Set PAN */ \
998:
#define EXIT_USER_ACCESS_CHECK(reg, tmp) \
ldr tmp, =has_pan; /* Get the addr of has_pan */ \
ldr reg, [tmp]; /* Read it */ \
cbz reg, 999f; /* If no PAN skip */ \
.inst 0xd500409f | (1 << 8); /* Set PAN */ \
999:
/*
* Some AArch64 CPUs speculate past an eret instruction. As the user may
* control the registers at this point add a speculation barrier usable on
* all AArch64 CPUs after the eret instruction.
* TODO: ARMv8.5 adds a specific instruction for this, we could use that
* if we know we are running on something that supports it.
*/
#define ERET \
eret; \
dsb sy; \
isb
#endif /* _MACHINE_ASM_H_ */