Commit 61a6fccc authored by Huacai Chen's avatar Huacai Chen
Browse files

LoongArch: Add unaligned access support 



Loongson-2 series (Loongson-2K500, Loongson-2K1000) don't support
unaligned access in hardware, while Loongson-3 series (Loongson-3A5000,
Loongson-3C5000) are configurable whether support unaligned access in
hardware. This patch add unaligned access emulation for those LoongArch
processors without hardware support.

Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent dbcd7f5f

Documentation/admin-guide/sysctl/kernel.rst

+4 −4
Original line number Diff line number Diff line
@@ -433,8 +433,8 @@ ignore-unaligned-usertrap 


On architectures where unaligned accesses cause traps, and where this

feature is supported (``CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN``;

currently, ``arc`` and ``ia64``), controls whether all unaligned traps

are logged.

currently, ``arc``, ``ia64`` and ``loongarch``), controls whether all

unaligned traps are logged.



= =============================================================

0 Log all unaligned accesses.
@@ -1457,8 +1457,8 @@ unaligned-trap 


On architectures where unaligned accesses cause traps, and where this

feature is supported (``CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW``; currently,

``arc`` and ``parisc``), controls whether unaligned traps are caught

and emulated (instead of failing).

``arc``, ``parisc`` and ``loongarch``), controls whether unaligned traps

are caught and emulated (instead of failing).



= ========================================================

0 Do not emulate unaligned accesses.

arch/loongarch/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -121,6 +121,8 @@ config LOONGARCH 
	select RTC_LIB

	select SMP

	select SPARSE_IRQ

	select SYSCTL_ARCH_UNALIGN_ALLOW

	select SYSCTL_ARCH_UNALIGN_NO_WARN

	select SYSCTL_EXCEPTION_TRACE

	select SWIOTLB

	select TRACE_IRQFLAGS_SUPPORT

arch/loongarch/include/asm/inst.h

+14 −0
Original line number Diff line number Diff line
@@ -76,6 +76,10 @@ enum reg2i12_op { 
	ldbu_op		= 0xa8,

	ldhu_op		= 0xa9,

	ldwu_op		= 0xaa,

	flds_op		= 0xac,

	fsts_op		= 0xad,

	fldd_op		= 0xae,

	fstd_op		= 0xaf,

};



enum reg2i14_op {
@@ -146,6 +150,10 @@ enum reg3_op { 
	ldxbu_op	= 0x7040,

	ldxhu_op	= 0x7048,

	ldxwu_op	= 0x7050,

	fldxs_op	= 0x7060,

	fldxd_op	= 0x7068,

	fstxs_op	= 0x7070,

	fstxd_op	= 0x7078,

	amswapw_op	= 0x70c0,

	amswapd_op	= 0x70c1,

	amaddw_op	= 0x70c2,
@@ -566,4 +574,10 @@ static inline void emit_##NAME(union loongarch_instruction *insn, \ 


DEF_EMIT_REG3SA2_FORMAT(alsld, alsld_op)



struct pt_regs;



void emulate_load_store_insn(struct pt_regs *regs, void __user *addr, unsigned int *pc);

unsigned long unaligned_read(void __user *addr, void *value, unsigned long n, bool sign);

unsigned long unaligned_write(void __user *addr, unsigned long value, unsigned long n);



#endif /* _ASM_INST_H */

arch/loongarch/include/asm/thread_info.h

+1 −1
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ struct thread_info { 
#define INIT_THREAD_INFO(tsk)			\

{						\

	.task		= &tsk,			\

	.flags		= 0,			\

	.flags		= _TIF_FIXADE,		\

	.cpu		= 0,			\

	.preempt_count	= INIT_PREEMPT_COUNT,	\

}

arch/loongarch/kernel/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -7,7 +7,8 @@ extra-y := vmlinux.lds 


obj-y		+= head.o cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \

		   traps.o irq.o idle.o process.o dma.o mem.o io.o reset.o switch.o \

		   elf.o syscall.o signal.o time.o topology.o inst.o ptrace.o vdso.o

		   elf.o syscall.o signal.o time.o topology.o inst.o ptrace.o vdso.o \

		   unaligned.o



obj-$(CONFIG_ACPI)		+= acpi.o

obj-$(CONFIG_EFI) 		+= efi.o