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bianbu-linux-6.6/arch/arm/include/asm/assembler.h
Ard Biesheuvel 450abd38fe ARM: kernel: use relative references for UP/SMP alternatives 
Currently, the .alt.smp.init section contains the virtual addresses
of the patch sites. Since patching may occur both before and after
switching into virtual mode, this requires some manual handling of
the address when applying the UP alternative.

Let's simplify this by using relative offsets in the table entries:
this allows us to simply add each entry's address to its contents,
regardless of whether we are running in virtual mode or not.

Reviewed-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-10-28 17:05:39 +01:00

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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* arch/arm/include/asm/assembler.h
*
* Copyright (C) 1996-2000 Russell King
*
* This file contains arm architecture specific defines
* for the different processors.
*
* Do not include any C declarations in this file - it is included by
* assembler source.
*/
#ifndef __ASM_ASSEMBLER_H__
#define __ASM_ASSEMBLER_H__
#ifndef __ASSEMBLY__
#error "Only include this from assembly code"
#endif
#include <asm/ptrace.h>
#include <asm/opcodes-virt.h>
#include <asm/asm-offsets.h>
#include <asm/page.h>
#include <asm/thread_info.h>
#include <asm/uaccess-asm.h>
#define IOMEM(x) (x)
/*
* Endian independent macros for shifting bytes within registers.
*/
#ifndef __ARMEB__
#define lspull lsr
#define lspush lsl
#define get_byte_0 lsl #0
#define get_byte_1 lsr #8
#define get_byte_2 lsr #16
#define get_byte_3 lsr #24
#define put_byte_0 lsl #0
#define put_byte_1 lsl #8
#define put_byte_2 lsl #16
#define put_byte_3 lsl #24
#else
#define lspull lsl
#define lspush lsr
#define get_byte_0 lsr #24
#define get_byte_1 lsr #16
#define get_byte_2 lsr #8
#define get_byte_3 lsl #0
#define put_byte_0 lsl #24
#define put_byte_1 lsl #16
#define put_byte_2 lsl #8
#define put_byte_3 lsl #0
#endif
/* Select code for any configuration running in BE8 mode */
#ifdef CONFIG_CPU_ENDIAN_BE8
#define ARM_BE8(code...) code
#else
#define ARM_BE8(code...)
#endif
/*
* Data preload for architectures that support it
*/
#if __LINUX_ARM_ARCH__ >= 5
#define PLD(code...) code
#else
#define PLD(code...)
#endif
/*
* This can be used to enable code to cacheline align the destination
* pointer when bulk writing to memory. Experiments on StrongARM and
* XScale didn't show this a worthwhile thing to do when the cache is not
* set to write-allocate (this would need further testing on XScale when WA
* is used).
*
* On Feroceon there is much to gain however, regardless of cache mode.
*/
#ifdef CONFIG_CPU_FEROCEON
#define CALGN(code...) code
#else
#define CALGN(code...)
#endif
#define IMM12_MASK 0xfff
/*
* Enable and disable interrupts
*/
#if __LINUX_ARM_ARCH__ >= 6
.macro disable_irq_notrace
cpsid i
.endm
.macro enable_irq_notrace
cpsie i
.endm
#else
.macro disable_irq_notrace
msr cpsr_c, #PSR_I_BIT | SVC_MODE
.endm
.macro enable_irq_notrace
msr cpsr_c, #SVC_MODE
.endm
#endif
.macro asm_trace_hardirqs_off, save=1
#if defined(CONFIG_TRACE_IRQFLAGS)
.if \save
stmdb sp!, {r0-r3, ip, lr}
.endif
bl trace_hardirqs_off
.if \save
ldmia sp!, {r0-r3, ip, lr}
.endif
#endif
.endm
.macro asm_trace_hardirqs_on, cond=al, save=1
#if defined(CONFIG_TRACE_IRQFLAGS)
/*
* actually the registers should be pushed and pop'd conditionally, but
* after bl the flags are certainly clobbered
*/
.if \save
stmdb sp!, {r0-r3, ip, lr}
.endif
bl\cond trace_hardirqs_on
.if \save
ldmia sp!, {r0-r3, ip, lr}
.endif
#endif
.endm
.macro disable_irq, save=1
disable_irq_notrace
asm_trace_hardirqs_off \save
.endm
.macro enable_irq
asm_trace_hardirqs_on
enable_irq_notrace
.endm
/*
* Save the current IRQ state and disable IRQs. Note that this macro
* assumes FIQs are enabled, and that the processor is in SVC mode.
*/
.macro save_and_disable_irqs, oldcpsr
#ifdef CONFIG_CPU_V7M
mrs \oldcpsr, primask
#else
mrs \oldcpsr, cpsr
#endif
disable_irq
.endm
.macro save_and_disable_irqs_notrace, oldcpsr
#ifdef CONFIG_CPU_V7M
mrs \oldcpsr, primask
#else
mrs \oldcpsr, cpsr
#endif
disable_irq_notrace
.endm
/*
* Restore interrupt state previously stored in a register. We don't
* guarantee that this will preserve the flags.
*/
.macro restore_irqs_notrace, oldcpsr
#ifdef CONFIG_CPU_V7M
msr primask, \oldcpsr
#else
msr cpsr_c, \oldcpsr
#endif
.endm
.macro restore_irqs, oldcpsr
tst \oldcpsr, #PSR_I_BIT
asm_trace_hardirqs_on cond=eq
restore_irqs_notrace \oldcpsr
.endm
/*
* Assembly version of "adr rd, BSYM(sym)". This should only be used to
* reference local symbols in the same assembly file which are to be
* resolved by the assembler. Other usage is undefined.
*/
.irp c,,eq,ne,cs,cc,mi,pl,vs,vc,hi,ls,ge,lt,gt,le,hs,lo
.macro badr\c, rd, sym
#ifdef CONFIG_THUMB2_KERNEL
adr\c \rd, \sym + 1
#else
adr\c \rd, \sym
#endif
.endm
.endr
/*
* Get current thread_info.
*/
.macro get_thread_info, rd
ARM( mov \rd, sp, lsr #THREAD_SIZE_ORDER + PAGE_SHIFT )
THUMB( mov \rd, sp )
THUMB( lsr \rd, \rd, #THREAD_SIZE_ORDER + PAGE_SHIFT )
mov \rd, \rd, lsl #THREAD_SIZE_ORDER + PAGE_SHIFT
.endm
/*
* Increment/decrement the preempt count.
*/
#ifdef CONFIG_PREEMPT_COUNT
.macro inc_preempt_count, ti, tmp
ldr \tmp, [\ti, #TI_PREEMPT] @ get preempt count
add \tmp, \tmp, #1 @ increment it
str \tmp, [\ti, #TI_PREEMPT]
.endm
.macro dec_preempt_count, ti, tmp
ldr \tmp, [\ti, #TI_PREEMPT] @ get preempt count
sub \tmp, \tmp, #1 @ decrement it
str \tmp, [\ti, #TI_PREEMPT]
.endm
.macro dec_preempt_count_ti, ti, tmp
get_thread_info \ti
dec_preempt_count \ti, \tmp
.endm
#else
.macro inc_preempt_count, ti, tmp
.endm
.macro dec_preempt_count, ti, tmp
.endm
.macro dec_preempt_count_ti, ti, tmp
.endm
#endif
#define USERL(l, x...) \
9999: x; \
.pushsection __ex_table,"a"; \
.align 3; \
.long 9999b,l; \
.popsection
#define USER(x...) USERL(9001f, x)
#ifdef CONFIG_SMP
#define ALT_SMP(instr...) \
9998: instr
/*
* Note: if you get assembler errors from ALT_UP() when building with
* CONFIG_THUMB2_KERNEL, you almost certainly need to use
* ALT_SMP( W(instr) ... )
*/
#define ALT_UP(instr...) \
.pushsection ".alt.smp.init", "a" ;\
.long 9998b - . ;\
9997: instr ;\
.if . - 9997b == 2 ;\
nop ;\
.endif ;\
.if . - 9997b != 4 ;\
.error "ALT_UP() content must assemble to exactly 4 bytes";\
.endif ;\
.popsection
#define ALT_UP_B(label) \
.pushsection ".alt.smp.init", "a" ;\
.long 9998b - . ;\
W(b) . + (label - 9998b) ;\
.popsection
#else
#define ALT_SMP(instr...)
#define ALT_UP(instr...) instr
#define ALT_UP_B(label) b label
#endif
/*
* Instruction barrier
*/
.macro instr_sync
#if __LINUX_ARM_ARCH__ >= 7
isb
#elif __LINUX_ARM_ARCH__ == 6
mcr p15, 0, r0, c7, c5, 4
#endif
.endm
/*
* SMP data memory barrier
*/
.macro smp_dmb mode
#ifdef CONFIG_SMP
#if __LINUX_ARM_ARCH__ >= 7
.ifeqs "\mode","arm"
ALT_SMP(dmb ish)
.else
ALT_SMP(W(dmb) ish)
.endif
#elif __LINUX_ARM_ARCH__ == 6
ALT_SMP(mcr p15, 0, r0, c7, c10, 5) @ dmb
#else
#error Incompatible SMP platform
#endif
.ifeqs "\mode","arm"
ALT_UP(nop)
.else
ALT_UP(W(nop))
.endif
#endif
.endm
#if defined(CONFIG_CPU_V7M)
/*
* setmode is used to assert to be in svc mode during boot. For v7-M
* this is done in __v7m_setup, so setmode can be empty here.
*/
.macro setmode, mode, reg
.endm
#elif defined(CONFIG_THUMB2_KERNEL)
.macro setmode, mode, reg
mov \reg, #\mode
msr cpsr_c, \reg
.endm
#else
.macro setmode, mode, reg
msr cpsr_c, #\mode
.endm
#endif
/*
* Helper macro to enter SVC mode cleanly and mask interrupts. reg is
* a scratch register for the macro to overwrite.
*
* This macro is intended for forcing the CPU into SVC mode at boot time.
* you cannot return to the original mode.
*/
.macro safe_svcmode_maskall reg:req
#if __LINUX_ARM_ARCH__ >= 6 && !defined(CONFIG_CPU_V7M)
mrs \reg , cpsr
eor \reg, \reg, #HYP_MODE
tst \reg, #MODE_MASK
bic \reg , \reg , #MODE_MASK
orr \reg , \reg , #PSR_I_BIT | PSR_F_BIT | SVC_MODE
THUMB( orr \reg , \reg , #PSR_T_BIT )
bne 1f
orr \reg, \reg, #PSR_A_BIT
badr lr, 2f
msr spsr_cxsf, \reg
__MSR_ELR_HYP(14)
__ERET
1: msr cpsr_c, \reg
2:
#else
/*
* workaround for possibly broken pre-v6 hardware
* (akita, Sharp Zaurus C-1000, PXA270-based)
*/
setmode PSR_F_BIT | PSR_I_BIT | SVC_MODE, \reg
#endif
.endm
/*
* STRT/LDRT access macros with ARM and Thumb-2 variants
*/
#ifdef CONFIG_THUMB2_KERNEL
.macro usraccoff, instr, reg, ptr, inc, off, cond, abort, t=TUSER()
9999:
.if \inc == 1
\instr\()b\t\cond\().w \reg, [\ptr, #\off]
.elseif \inc == 4
\instr\t\cond\().w \reg, [\ptr, #\off]
.else
.error "Unsupported inc macro argument"
.endif
.pushsection __ex_table,"a"
.align 3
.long 9999b, \abort
.popsection
.endm
.macro usracc, instr, reg, ptr, inc, cond, rept, abort
@ explicit IT instruction needed because of the label
@ introduced by the USER macro
.ifnc \cond,al
.if \rept == 1
itt \cond
.elseif \rept == 2
ittt \cond
.else
.error "Unsupported rept macro argument"
.endif
.endif
@ Slightly optimised to avoid incrementing the pointer twice
usraccoff \instr, \reg, \ptr, \inc, 0, \cond, \abort
.if \rept == 2
usraccoff \instr, \reg, \ptr, \inc, \inc, \cond, \abort
.endif
add\cond \ptr, #\rept * \inc
.endm
#else /* !CONFIG_THUMB2_KERNEL */
.macro usracc, instr, reg, ptr, inc, cond, rept, abort, t=TUSER()
.rept \rept
9999:
.if \inc == 1
\instr\()b\t\cond \reg, [\ptr], #\inc
.elseif \inc == 4
\instr\t\cond \reg, [\ptr], #\inc
.else
.error "Unsupported inc macro argument"
.endif
.pushsection __ex_table,"a"
.align 3
.long 9999b, \abort
.popsection
.endr
.endm
#endif /* CONFIG_THUMB2_KERNEL */
.macro strusr, reg, ptr, inc, cond=al, rept=1, abort=9001f
usracc str, \reg, \ptr, \inc, \cond, \rept, \abort
.endm
.macro ldrusr, reg, ptr, inc, cond=al, rept=1, abort=9001f
usracc ldr, \reg, \ptr, \inc, \cond, \rept, \abort
.endm
/* Utility macro for declaring string literals */
.macro string name:req, string
.type \name , #object
\name:
.asciz "\string"
.size \name , . - \name
.endm
.irp c,,eq,ne,cs,cc,mi,pl,vs,vc,hi,ls,ge,lt,gt,le,hs,lo
.macro ret\c, reg
#if __LINUX_ARM_ARCH__ < 6
mov\c pc, \reg
#else
.ifeqs "\reg", "lr"
bx\c \reg
.else
mov\c pc, \reg
.endif
#endif
.endm
.endr
.macro ret.w, reg
ret \reg
#ifdef CONFIG_THUMB2_KERNEL
nop
#endif
.endm
.macro bug, msg, line
#ifdef CONFIG_THUMB2_KERNEL
1: .inst 0xde02
#else
1: .inst 0xe7f001f2
#endif
#ifdef CONFIG_DEBUG_BUGVERBOSE
.pushsection .rodata.str, "aMS", %progbits, 1
2: .asciz "\msg"
.popsection
.pushsection __bug_table, "aw"
.align 2
.word 1b, 2b
.hword \line
.popsection
#endif
.endm
#ifdef CONFIG_KPROBES
#define _ASM_NOKPROBE(entry) \
.pushsection "_kprobe_blacklist", "aw" ; \
.balign 4 ; \
.long entry; \
.popsection
#else
#define _ASM_NOKPROBE(entry)
#endif
.macro __adldst_l, op, reg, sym, tmp, c
.if __LINUX_ARM_ARCH__ < 7
ldr\c \tmp, .La\@
.subsection 1
.align 2
.La\@: .long \sym - .Lpc\@
.previous
.else
.ifnb \c
THUMB( ittt \c )
.endif
movw\c \tmp, #:lower16:\sym - .Lpc\@
movt\c \tmp, #:upper16:\sym - .Lpc\@
.endif
#ifndef CONFIG_THUMB2_KERNEL
.set .Lpc\@, . + 8 // PC bias
.ifc \op, add
add\c \reg, \tmp, pc
.else
\op\c \reg, [pc, \tmp]
.endif
#else
.Lb\@: add\c \tmp, \tmp, pc
/*
* In Thumb-2 builds, the PC bias depends on whether we are currently
* emitting into a .arm or a .thumb section. The size of the add opcode
* above will be 2 bytes when emitting in Thumb mode and 4 bytes when
* emitting in ARM mode, so let's use this to account for the bias.
*/
.set .Lpc\@, . + (. - .Lb\@)
.ifnc \op, add
\op\c \reg, [\tmp]
.endif
#endif
.endm
/*
* mov_l - move a constant value or [relocated] address into a register
*/
.macro mov_l, dst:req, imm:req
.if __LINUX_ARM_ARCH__ < 7
ldr \dst, =\imm
.else
movw \dst, #:lower16:\imm
movt \dst, #:upper16:\imm
.endif
.endm
/*
* adr_l - adr pseudo-op with unlimited range
*
* @dst: destination register
* @sym: name of the symbol
* @cond: conditional opcode suffix
*/
.macro adr_l, dst:req, sym:req, cond
__adldst_l add, \dst, \sym, \dst, \cond
.endm
/*
* ldr_l - ldr <literal> pseudo-op with unlimited range
*
* @dst: destination register
* @sym: name of the symbol
* @cond: conditional opcode suffix
*/
.macro ldr_l, dst:req, sym:req, cond
__adldst_l ldr, \dst, \sym, \dst, \cond
.endm
/*
* str_l - str <literal> pseudo-op with unlimited range
*
* @src: source register
* @sym: name of the symbol
* @tmp: mandatory scratch register
* @cond: conditional opcode suffix
*/
.macro str_l, src:req, sym:req, tmp:req, cond
__adldst_l str, \src, \sym, \tmp, \cond
.endm
#endif /* __ASM_ASSEMBLER_H__ */
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