From: Vincent Chen vincentc@andestech.com
[ Upstream commit ed32949e0acb73e7bc054bb02e0453d4d561ceda ]
In order for kernel to capture each denormalized output, the UDF trapping enable bit is always raised in $fpcsr. Because underflow case will issue not an underflow exception but also an inexact exception, it causes that the IEX, IEX cumulative exception, flag in $fpcsr to be raised in each denormalized output handling. To make the emulation transparent to the user, the emulator needs to clear the IEX flag in $fpcsr if the result is a denormalized number. However, if the IEX flag has been raised before this floating point emulation, this cleanup may be incorrect. To avoid the IEX flags in $fpcsr be raised in each denormalized output handling, the IEX trap shall be always enabled.
Signed-off-by: Vincent Chen vincentc@andestech.com Acked-by: Greentime Hu greentime@andestech.com Signed-off-by: Greentime Hu greentime@andestech.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/nds32/include/asm/bitfield.h | 2 +- arch/nds32/include/asm/fpu.h | 2 +- arch/nds32/include/asm/syscalls.h | 2 +- arch/nds32/include/uapi/asm/fp_udfiex_crtl.h | 16 ++++++++++++ arch/nds32/include/uapi/asm/sigcontext.h | 24 ++++++++++++------ arch/nds32/include/uapi/asm/udftrap.h | 13 ---------- arch/nds32/include/uapi/asm/unistd.h | 4 +-- arch/nds32/kernel/fpu.c | 15 +++++------ arch/nds32/kernel/sys_nds32.c | 26 +++++++++++--------- 9 files changed, 58 insertions(+), 46 deletions(-) create mode 100644 arch/nds32/include/uapi/asm/fp_udfiex_crtl.h delete mode 100644 arch/nds32/include/uapi/asm/udftrap.h
diff --git a/arch/nds32/include/asm/bitfield.h b/arch/nds32/include/asm/bitfield.h index 7414fcbbab4e..03bbb6d27828 100644 --- a/arch/nds32/include/asm/bitfield.h +++ b/arch/nds32/include/asm/bitfield.h @@ -937,7 +937,7 @@ #define FPCSR_mskDNIT ( 0x1 << FPCSR_offDNIT ) #define FPCSR_mskRIT ( 0x1 << FPCSR_offRIT ) #define FPCSR_mskALL (FPCSR_mskIVO | FPCSR_mskDBZ | FPCSR_mskOVF | FPCSR_mskUDF | FPCSR_mskIEX) -#define FPCSR_mskALLE_NO_UDFE (FPCSR_mskIVOE | FPCSR_mskDBZE | FPCSR_mskOVFE | FPCSR_mskIEXE) +#define FPCSR_mskALLE_NO_UDF_IEXE (FPCSR_mskIVOE | FPCSR_mskDBZE | FPCSR_mskOVFE) #define FPCSR_mskALLE (FPCSR_mskIVOE | FPCSR_mskDBZE | FPCSR_mskOVFE | FPCSR_mskUDFE | FPCSR_mskIEXE) #define FPCSR_mskALLT (FPCSR_mskIVOT | FPCSR_mskDBZT | FPCSR_mskOVFT | FPCSR_mskUDFT | FPCSR_mskIEXT |FPCSR_mskDNIT | FPCSR_mskRIT)
diff --git a/arch/nds32/include/asm/fpu.h b/arch/nds32/include/asm/fpu.h index 019f1bcfc5ee..8294ed4aaa2c 100644 --- a/arch/nds32/include/asm/fpu.h +++ b/arch/nds32/include/asm/fpu.h @@ -36,7 +36,7 @@ extern int do_fpuemu(struct pt_regs *regs, struct fpu_struct *fpu); * enabled by default and kerenl will re-execute it by fpu emulator * when getting underflow exception. */ -#define FPCSR_INIT FPCSR_mskUDFE +#define FPCSR_INIT (FPCSR_mskUDFE | FPCSR_mskIEXE) #else #define FPCSR_INIT 0x0UL #endif diff --git a/arch/nds32/include/asm/syscalls.h b/arch/nds32/include/asm/syscalls.h index da32101b455d..b9c9becce5d6 100644 --- a/arch/nds32/include/asm/syscalls.h +++ b/arch/nds32/include/asm/syscalls.h @@ -7,7 +7,7 @@ asmlinkage long sys_cacheflush(unsigned long addr, unsigned long len, unsigned int op); asmlinkage long sys_fadvise64_64_wrapper(int fd, int advice, loff_t offset, loff_t len); asmlinkage long sys_rt_sigreturn_wrapper(void); -asmlinkage long sys_udftrap(int option); +asmlinkage long sys_fp_udfiex_crtl(int cmd, int act);
#include <asm-generic/syscalls.h>
diff --git a/arch/nds32/include/uapi/asm/fp_udfiex_crtl.h b/arch/nds32/include/uapi/asm/fp_udfiex_crtl.h new file mode 100644 index 000000000000..d54a5d6c6538 --- /dev/null +++ b/arch/nds32/include/uapi/asm/fp_udfiex_crtl.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2005-2019 Andes Technology Corporation */ +#ifndef _FP_UDF_IEX_CRTL_H +#define _FP_UDF_IEX_CRTL_H + +/* + * The cmd list of sys_fp_udfiex_crtl() + */ +/* Disable UDF or IEX trap based on the content of parameter act */ +#define DISABLE_UDF_IEX_TRAP 0 +/* Enable UDF or IEX trap based on the content of parameter act */ +#define ENABLE_UDF_IEX_TRAP 1 +/* Get current status of UDF and IEX trap */ +#define GET_UDF_IEX_TRAP 2 + +#endif /* _FP_UDF_IEX_CRTL_H */ diff --git a/arch/nds32/include/uapi/asm/sigcontext.h b/arch/nds32/include/uapi/asm/sigcontext.h index 58afc416473e..b53634033e32 100644 --- a/arch/nds32/include/uapi/asm/sigcontext.h +++ b/arch/nds32/include/uapi/asm/sigcontext.h @@ -13,14 +13,24 @@ struct fpu_struct { unsigned long long fd_regs[32]; unsigned long fpcsr; /* - * UDF_trap is used to recognize whether underflow trap is enabled - * or not. When UDF_trap == 1, this process will be traped and then - * get a SIGFPE signal when encountering an underflow exception. - * UDF_trap is only modified through setfputrap syscall. Therefore, - * UDF_trap needn't be saved or loaded to context in each context - * switch. + * When CONFIG_SUPPORT_DENORMAL_ARITHMETIC is defined, kernel prevents + * hardware from treating the denormalized output as an underflow case + * and rounding it to a normal number. Hence kernel enables the UDF and + * IEX trap in the fpcsr register to step in the calculation. + * However, the UDF and IEX trap enable bit in $fpcsr also lose + * their use. + * + * UDF_IEX_trap replaces the feature of UDF and IEX trap enable bit in + * $fpcsr to control the trap of underflow and inexact. The bit filed + * of UDF_IEX_trap is the same as $fpcsr, 10th bit is used to enable UDF + * exception trapping and 11th bit is used to enable IEX exception + * trapping. + * + * UDF_IEX_trap is only modified through fp_udfiex_crtl syscall. + * Therefore, UDF_IEX_trap needn't be saved and restored in each + * context switch. */ - unsigned long UDF_trap; + unsigned long UDF_IEX_trap; };
struct zol_struct { diff --git a/arch/nds32/include/uapi/asm/udftrap.h b/arch/nds32/include/uapi/asm/udftrap.h deleted file mode 100644 index 433f79d679c0..000000000000 --- a/arch/nds32/include/uapi/asm/udftrap.h +++ /dev/null @@ -1,13 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* Copyright (C) 2005-2018 Andes Technology Corporation */ -#ifndef _ASM_SETFPUTRAP -#define _ASM_SETFPUTRAP - -/* - * Options for setfputrap system call - */ -#define DISABLE_UDFTRAP 0 /* disable underflow exception trap */ -#define ENABLE_UDFTRAP 1 /* enable undeflos exception trap */ -#define GET_UDFTRAP 2 /* only get undeflos exception trap status */ - -#endif /* _ASM_CACHECTL */ diff --git a/arch/nds32/include/uapi/asm/unistd.h b/arch/nds32/include/uapi/asm/unistd.h index 4ec8f543103f..6b9ff90e3ae5 100644 --- a/arch/nds32/include/uapi/asm/unistd.h +++ b/arch/nds32/include/uapi/asm/unistd.h @@ -11,6 +11,6 @@
/* Additional NDS32 specific syscalls. */ #define __NR_cacheflush (__NR_arch_specific_syscall) -#define __NR_udftrap (__NR_arch_specific_syscall + 1) +#define __NR_fp_udfiex_crtl (__NR_arch_specific_syscall + 1) __SYSCALL(__NR_cacheflush, sys_cacheflush) -__SYSCALL(__NR_udftrap, sys_udftrap) +__SYSCALL(__NR_fp_udfiex_crtl, sys_fp_udfiex_crtl) diff --git a/arch/nds32/kernel/fpu.c b/arch/nds32/kernel/fpu.c index fddd40c7a16f..cf0b8760f261 100644 --- a/arch/nds32/kernel/fpu.c +++ b/arch/nds32/kernel/fpu.c @@ -14,7 +14,7 @@ const struct fpu_struct init_fpuregs = { .fd_regs = {[0 ... 31] = sNAN64}, .fpcsr = FPCSR_INIT, #if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC) - .UDF_trap = 0 + .UDF_IEX_trap = 0 #endif };
@@ -178,7 +178,7 @@ inline void do_fpu_context_switch(struct pt_regs *regs) /* First time FPU user. */ load_fpu(&init_fpuregs); #if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC) - current->thread.fpu.UDF_trap = init_fpuregs.UDF_trap; + current->thread.fpu.UDF_IEX_trap = init_fpuregs.UDF_IEX_trap; #endif set_used_math(); } @@ -206,7 +206,7 @@ inline void handle_fpu_exception(struct pt_regs *regs) unsigned int fpcsr; int si_code = 0, si_signo = SIGFPE; #if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC) - unsigned long redo_except = FPCSR_mskDNIT|FPCSR_mskUDFT; + unsigned long redo_except = FPCSR_mskDNIT|FPCSR_mskUDFT|FPCSR_mskIEXT; #else unsigned long redo_except = FPCSR_mskDNIT; #endif @@ -215,21 +215,18 @@ inline void handle_fpu_exception(struct pt_regs *regs) fpcsr = current->thread.fpu.fpcsr;
if (fpcsr & redo_except) { -#if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC) - if (fpcsr & FPCSR_mskUDFT) - current->thread.fpu.fpcsr &= ~FPCSR_mskIEX; -#endif si_signo = do_fpuemu(regs, ¤t->thread.fpu); fpcsr = current->thread.fpu.fpcsr; - if (!si_signo) + if (!si_signo) { + current->thread.fpu.fpcsr &= ~(redo_except); goto done; + } } else if (fpcsr & FPCSR_mskRIT) { if (!user_mode(regs)) do_exit(SIGILL); si_signo = SIGILL; }
- switch (si_signo) { case SIGFPE: fill_sigfpe_signo(fpcsr, &si_code); diff --git a/arch/nds32/kernel/sys_nds32.c b/arch/nds32/kernel/sys_nds32.c index 0835277636ce..cb2d1e219bb3 100644 --- a/arch/nds32/kernel/sys_nds32.c +++ b/arch/nds32/kernel/sys_nds32.c @@ -6,8 +6,8 @@
#include <asm/cachectl.h> #include <asm/proc-fns.h> -#include <asm/udftrap.h> #include <asm/fpu.h> +#include <asm/fp_udfiex_crtl.h>
SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len, unsigned long, prot, unsigned long, flags, @@ -51,31 +51,33 @@ SYSCALL_DEFINE3(cacheflush, unsigned int, start, unsigned int, end, int, cache) return 0; }
-SYSCALL_DEFINE1(udftrap, int, option) +SYSCALL_DEFINE2(fp_udfiex_crtl, unsigned int, cmd, unsigned int, act) { #if IS_ENABLED(CONFIG_SUPPORT_DENORMAL_ARITHMETIC) - int old_udftrap; + int old_udf_iex;
if (!used_math()) { load_fpu(&init_fpuregs); - current->thread.fpu.UDF_trap = init_fpuregs.UDF_trap; + current->thread.fpu.UDF_IEX_trap = init_fpuregs.UDF_IEX_trap; set_used_math(); }
- old_udftrap = current->thread.fpu.UDF_trap; - switch (option) { - case DISABLE_UDFTRAP: - current->thread.fpu.UDF_trap = 0; + old_udf_iex = current->thread.fpu.UDF_IEX_trap; + act &= (FPCSR_mskUDFE | FPCSR_mskIEXE); + + switch (cmd) { + case DISABLE_UDF_IEX_TRAP: + current->thread.fpu.UDF_IEX_trap &= ~act; break; - case ENABLE_UDFTRAP: - current->thread.fpu.UDF_trap = FPCSR_mskUDFE; + case ENABLE_UDF_IEX_TRAP: + current->thread.fpu.UDF_IEX_trap |= act; break; - case GET_UDFTRAP: + case GET_UDF_IEX_TRAP: break; default: return -EINVAL; } - return old_udftrap; + return old_udf_iex; #else return -ENOTSUPP; #endif