linux/arch/arm/mm/tlb-v6.S
Nick Desaulniers a2faac3986 ARM: 9263/1: use .arch directives instead of assembler command line flags
Similar to commit a6c30873ee ("ARM: 8989/1: use .fpu assembler
directives instead of assembler arguments").

GCC and GNU binutils support setting the "sub arch" via -march=,
-Wa,-march, target function attribute, and .arch assembler directive.

Clang was missing support for -Wa,-march=, but this was implemented in
clang-13.

The behavior of both GCC and Clang is to
prefer -Wa,-march= over -march= for assembler and assembler-with-cpp
sources, but Clang will warn about the -march= being unused.

clang: warning: argument unused during compilation: '-march=armv6k'
[-Wunused-command-line-argument]

Since most assembler is non-conditionally assembled with one sub arch
(modulo arch/arm/delay-loop.S which conditionally is assembled as armv4
based on CONFIG_ARCH_RPC, and arch/arm/mach-at91/pm-suspend.S which is
conditionally assembled as armv7-a based on CONFIG_CPU_V7), prefer the
.arch assembler directive.

Add a few more instances found in compile testing as found by Arnd and
Nathan.

Link: 1d51c699b9
Link: https://bugs.llvm.org/show_bug.cgi?id=48894
Link: https://github.com/ClangBuiltLinux/linux/issues/1195
Link: https://github.com/ClangBuiltLinux/linux/issues/1315

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-11-08 18:36:17 +00:00

93 lines
2.5 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* linux/arch/arm/mm/tlb-v6.S
*
* Copyright (C) 1997-2002 Russell King
*
* ARM architecture version 6 TLB handling functions.
* These assume a split I/D TLB.
*/
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/asm-offsets.h>
#include <asm/assembler.h>
#include <asm/page.h>
#include <asm/tlbflush.h>
#include "proc-macros.S"
#define HARVARD_TLB
.arch armv6
/*
* v6wbi_flush_user_tlb_range(start, end, vma)
*
* Invalidate a range of TLB entries in the specified address space.
*
* - start - start address (may not be aligned)
* - end - end address (exclusive, may not be aligned)
* - vma - vm_area_struct describing address range
*
* It is assumed that:
* - the "Invalidate single entry" instruction will invalidate
* both the I and the D TLBs on Harvard-style TLBs
*/
ENTRY(v6wbi_flush_user_tlb_range)
vma_vm_mm r3, r2 @ get vma->vm_mm
mov ip, #0
mmid r3, r3 @ get vm_mm->context.id
mcr p15, 0, ip, c7, c10, 4 @ drain write buffer
mov r0, r0, lsr #PAGE_SHIFT @ align address
mov r1, r1, lsr #PAGE_SHIFT
asid r3, r3 @ mask ASID
orr r0, r3, r0, lsl #PAGE_SHIFT @ Create initial MVA
mov r1, r1, lsl #PAGE_SHIFT
vma_vm_flags r2, r2 @ get vma->vm_flags
1:
#ifdef HARVARD_TLB
mcr p15, 0, r0, c8, c6, 1 @ TLB invalidate D MVA (was 1)
tst r2, #VM_EXEC @ Executable area ?
mcrne p15, 0, r0, c8, c5, 1 @ TLB invalidate I MVA (was 1)
#else
mcr p15, 0, r0, c8, c7, 1 @ TLB invalidate MVA (was 1)
#endif
add r0, r0, #PAGE_SZ
cmp r0, r1
blo 1b
mcr p15, 0, ip, c7, c10, 4 @ data synchronization barrier
ret lr
/*
* v6wbi_flush_kern_tlb_range(start,end)
*
* Invalidate a range of kernel TLB entries
*
* - start - start address (may not be aligned)
* - end - end address (exclusive, may not be aligned)
*/
ENTRY(v6wbi_flush_kern_tlb_range)
mov r2, #0
mcr p15, 0, r2, c7, c10, 4 @ drain write buffer
mov r0, r0, lsr #PAGE_SHIFT @ align address
mov r1, r1, lsr #PAGE_SHIFT
mov r0, r0, lsl #PAGE_SHIFT
mov r1, r1, lsl #PAGE_SHIFT
1:
#ifdef HARVARD_TLB
mcr p15, 0, r0, c8, c6, 1 @ TLB invalidate D MVA
mcr p15, 0, r0, c8, c5, 1 @ TLB invalidate I MVA
#else
mcr p15, 0, r0, c8, c7, 1 @ TLB invalidate MVA
#endif
add r0, r0, #PAGE_SZ
cmp r0, r1
blo 1b
mcr p15, 0, r2, c7, c10, 4 @ data synchronization barrier
mcr p15, 0, r2, c7, c5, 4 @ prefetch flush (isb)
ret lr
__INIT
/* define struct cpu_tlb_fns (see <asm/tlbflush.h> and proc-macros.S) */
define_tlb_functions v6wbi, v6wbi_tlb_flags