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authorVincent Chen <vincentc@andestech.com>2019-05-20 09:21:12 +0800
committerGreentime Hu <greentime@andestech.com>2019-05-31 15:23:26 +0800
commited32949e0acb73e7bc054bb02e0453d4d561ceda (patch)
treef582241cdd3450e01fe6d1cf508a3e3a8211c675 /arch/nds32/kernel
parent8183db10db6377ac58ad048a4c827425a614695c (diff)
nds32: Avoid IEX status being incorrectly modified
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>
Diffstat (limited to 'arch/nds32/kernel')
-rw-r--r--arch/nds32/kernel/fpu.c15
-rw-r--r--arch/nds32/kernel/sys_nds32.c26
2 files changed, 20 insertions, 21 deletions
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, &current->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