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Loongson Binary Translation (LBT) is used to accelerate binary translation,
which contains 4 scratch registers (scr0 to scr3), x86/ARM eflags (eflags)
and x87 fpu stack pointer (ftop).
This patch support kernel to save/restore these registers, handle the LBT
exception and maintain sigcontext.
Signed-off-by: Qi Hu <huqi@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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The initial aim is to silence the following objtool warnings:
arch/loongarch/kernel/fpu.o: warning: objtool: _save_fp_context() falls through to next function fault()
arch/loongarch/kernel/fpu.o: warning: objtool: _restore_fp_context() falls through to next function fault()
arch/loongarch/kernel/fpu.o: warning: objtool: _save_lsx_context() falls through to next function fault()
arch/loongarch/kernel/fpu.o: warning: objtool: _restore_lsx_context() falls through to next function fault()
arch/loongarch/kernel/fpu.o: warning: objtool: _save_lasx_context() falls through to next function fault()
arch/loongarch/kernel/fpu.o: warning: objtool: _restore_lasx_context() falls through to next function fault()
Currently, SYM_FUNC_START()/SYM_FUNC_END() defines the symbol 'fault' as
SYM_T_FUNC which is STT_FUNC, the objtool warnings are generated through
the following code:
tools/objtool/include/objtool/check.h:
static inline struct symbol *insn_func(struct instruction *insn)
{
struct symbol *sym = insn->sym;
if (sym && sym->type != STT_FUNC)
sym = NULL;
return sym;
}
tools/objtool/check.c:
static int validate_branch(struct objtool_file *file, struct symbol *func,
struct instruction *insn, struct insn_state state)
{
...
if (func && insn_func(insn) && func != insn_func(insn)->pfunc) {
...
WARN("%s() falls through to next function %s()",
func->name, insn_func(insn)->name);
return 1;
}
...
}
We can see that the fixup can be a local label in the following code:
arch/loongarch/include/asm/asm-extable.h:
.pushsection __ex_table, "a"; \
.balign 4; \
.long ((insn) - .); \
.long ((fixup) - .); \
.short (type); \
.short (data); \
.popsection;
.macro _asm_extable, insn, fixup
__ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0)
.endm
Like arch/loongarch/lib/*.S, just define the symbol 'fault' as a local
label in fpu.S.
Before:
$ readelf -s arch/loongarch/kernel/fpu.o | awk -F: /fault/'{print $2}'
000000000000053c 8 FUNC GLOBAL DEFAULT 1 fault
After:
$ readelf -s arch/loongarch/kernel/fpu.o | awk -F: /fault/'{print $2}'
000000000000053c 0 NOTYPE LOCAL DEFAULT 1 .L_fpu_fault
Co-developed-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Commit ddb5cdbafaaad ("kbuild: generate KSYMTAB entries by modpost")
deprecated <asm/export.h>, which is now a wrapper of <linux/export.h>.
Replace #include <asm/export.h> with #include <linux/export.h>.
After all the <asm/export.h> lines are converted, <asm/export.h> and
<asm-generic/export.h> will be removed.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Add LoongArch's vector extensions support, which including 128bit LSX
(i.e., Loongson SIMD eXtension) and 256bit LASX (i.e., Loongson Advanced
SIMD eXtension).
Linux kernel doesn't use vector itself, it only handle exceptions and
context save/restore. So it only needs a subset of these instructions:
* Vector load/store: vld vst vldx vstx xvld xvst xvldx xvstx
* 8bit-elements move: vpickve2gr.b xvpickve2gr.b vinsgr2vr.b xvinsgr2vr.b
* 16bit-elements move: vpickve2gr.h xvpickve2gr.h vinsgr2vr.h xvinsgr2vr.h
* 32bit-elements move: vpickve2gr.w xvpickve2gr.w vinsgr2vr.w xvinsgr2vr.w
* 64bit-elements move: vpickve2gr.d xvpickve2gr.d vinsgr2vr.d xvinsgr2vr.d
* Elements permute: vpermi.w vpermi.d xvpermi.w xvpermi.d xvpermi.q
Introduce AS_HAS_LSX_EXTENSION and AS_HAS_LASX_EXTENSION to avoid non-
vector toolchains complains unsupported instructions.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Consolidate all the __ex_table constuction code with a _ASM_EXTABLE or
_asm_extable helper.
There should be no functional change as a result of this patch.
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Reflow the *.S files for better stylistic consistency, namely hard tabs
after mnemonic position, and vertical alignment of the first operand
with hard tabs. Tab width is obviously 8. Some pre-existing intra-block
vertical alignments are preserved.
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Some of the assembly code in the LoongArch port likely originated
from a time when the assembler did not support pseudo-instructions like
"move" or "jr", so the desugared form was used and readability suffers
(to a minor degree) as a result.
As the upstream toolchain supports these pseudo-instructions from the
beginning, migrate the existing few usages to them for better
readability.
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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The `vcsr` only exists in the old hardware design, it isn't used in any
shipped hardware from Loongson-3A5000 on. Both scalar FP and LSX/LASX
instructions use the `fcsr` as their control and status registers now.
For example, the RM control bit in fcsr0 is shared by FP, LSX and LASX
instructions.
Particularly, fcsr16 to fcsr31 are reserved for LSX/LASX now, access to
these registers has no visible effect if LSX/LASX is enabled, and will
cause SXD/ASXD exceptions if LSX/LASX is not enabled.
So, mentions of vcsr are obsolete in the first place (it was just used
for debugging), let's remove them.
Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Qi Hu <huqi@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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Add process management support for LoongArch, including: thread info
definition, context switch and process tracing.
Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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