mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-24 15:56:49 +00:00
0b18fca82f
Refreshed all patches. Compile-tested on: cns3xxx Runtime-tested on: cns3xxx Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
138 lines
4.1 KiB
Diff
138 lines
4.1 KiB
Diff
From: Manuel Lauss <manuel.lauss@gmail.com>
|
|
Subject: [RFC PATCH v4 2/2] MIPS: make FPU emulator optional
|
|
|
|
This small patch makes the MIPS FPU emulator optional. The kernel
|
|
kills float-users on systems without a hardware FPU by sending a SIGILL.
|
|
|
|
Disabling the emulator shrinks vmlinux by about 54kBytes (32bit,
|
|
optimizing for size).
|
|
|
|
Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
|
|
---
|
|
v4: rediffed because of patch 1/2, should now work with micromips as well
|
|
v3: updated patch description with size savings.
|
|
v2: incorporated changes suggested by Jonas Gorski
|
|
force the fpu emulator on for micromips: relocating the parts
|
|
of the mmips code in the emulator to other areas would be a
|
|
much larger change; I went the cheap route instead with this.
|
|
|
|
arch/mips/Kbuild | 2 +-
|
|
arch/mips/Kconfig | 14 ++++++++++++++
|
|
arch/mips/include/asm/fpu.h | 5 +++--
|
|
arch/mips/include/asm/fpu_emulator.h | 15 +++++++++++++++
|
|
4 files changed, 33 insertions(+), 3 deletions(-)
|
|
|
|
--- a/arch/mips/Kconfig
|
|
+++ b/arch/mips/Kconfig
|
|
@@ -2891,6 +2891,20 @@ config MIPS_O32_FP64_SUPPORT
|
|
|
|
If unsure, say N.
|
|
|
|
+config MIPS_FPU_EMULATOR
|
|
+ bool "MIPS FPU Emulator"
|
|
+ default y
|
|
+ help
|
|
+ This option lets you disable the built-in MIPS FPU (Coprocessor 1)
|
|
+ emulator, which handles floating-point instructions on processors
|
|
+ without a hardware FPU. It is generally a good idea to keep the
|
|
+ emulator built-in, unless you are perfectly sure you have a
|
|
+ complete soft-float environment. With the emulator disabled, all
|
|
+ users of float operations will be killed with an illegal instr-
|
|
+ uction exception.
|
|
+
|
|
+ Say Y, please.
|
|
+
|
|
config USE_OF
|
|
bool
|
|
select OF
|
|
--- a/arch/mips/Makefile
|
|
+++ b/arch/mips/Makefile
|
|
@@ -315,7 +315,7 @@ OBJCOPYFLAGS += --remove-section=.regin
|
|
head-y := arch/mips/kernel/head.o
|
|
|
|
libs-y += arch/mips/lib/
|
|
-libs-y += arch/mips/math-emu/
|
|
+libs-$(CONFIG_MIPS_FPU_EMULATOR) += arch/mips/math-emu/
|
|
|
|
# See arch/mips/Kbuild for content of core part of the kernel
|
|
core-y += arch/mips/
|
|
--- a/arch/mips/include/asm/fpu.h
|
|
+++ b/arch/mips/include/asm/fpu.h
|
|
@@ -230,8 +230,10 @@ static inline int init_fpu(void)
|
|
/* Restore FRE */
|
|
write_c0_config5(config5);
|
|
enable_fpu_hazard();
|
|
- } else
|
|
+ } else if (IS_ENABLED(CONFIG_MIPS_FPU_EMULATOR))
|
|
fpu_emulator_init_fpu();
|
|
+ else
|
|
+ ret = SIGILL;
|
|
|
|
return ret;
|
|
}
|
|
--- a/arch/mips/include/asm/fpu_emulator.h
|
|
+++ b/arch/mips/include/asm/fpu_emulator.h
|
|
@@ -30,6 +30,7 @@
|
|
#include <asm/local.h>
|
|
#include <asm/processor.h>
|
|
|
|
+#ifdef CONFIG_MIPS_FPU_EMULATOR
|
|
#ifdef CONFIG_DEBUG_FS
|
|
|
|
struct mips_fpu_emulator_stats {
|
|
@@ -179,6 +180,16 @@ do { \
|
|
extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
|
|
struct mips_fpu_struct *ctx, int has_fpu,
|
|
void __user **fault_addr);
|
|
+#else /* no CONFIG_MIPS_FPU_EMULATOR */
|
|
+static inline int fpu_emulator_cop1Handler(struct pt_regs *xcp,
|
|
+ struct mips_fpu_struct *ctx, int has_fpu,
|
|
+ void __user **fault_addr)
|
|
+{
|
|
+ *fault_addr = NULL;
|
|
+ return SIGILL; /* we don't speak MIPS FPU */
|
|
+}
|
|
+#endif /* CONFIG_MIPS_FPU_EMULATOR */
|
|
+
|
|
void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr,
|
|
struct task_struct *tsk);
|
|
int process_fpemu_return(int sig, void __user *fault_addr,
|
|
--- a/arch/mips/include/asm/dsemul.h
|
|
+++ b/arch/mips/include/asm/dsemul.h
|
|
@@ -41,6 +41,7 @@ struct task_struct;
|
|
extern int mips_dsemul(struct pt_regs *regs, mips_instruction ir,
|
|
unsigned long branch_pc, unsigned long cont_pc);
|
|
|
|
+#ifdef CONFIG_MIPS_FPU_EMULATOR
|
|
/**
|
|
* do_dsemulret() - Return from a delay slot 'emulation' frame
|
|
* @xcp: User thread register context.
|
|
@@ -88,5 +89,27 @@ extern bool dsemul_thread_rollback(struc
|
|
* before @mm is freed in order to avoid memory leaks.
|
|
*/
|
|
extern void dsemul_mm_cleanup(struct mm_struct *mm);
|
|
+#else
|
|
+static inline bool do_dsemulret(struct pt_regs *xcp)
|
|
+{
|
|
+ return false;
|
|
+}
|
|
+
|
|
+static inline bool dsemul_thread_cleanup(struct task_struct *tsk)
|
|
+{
|
|
+ return false;
|
|
+}
|
|
+
|
|
+static inline bool dsemul_thread_rollback(struct pt_regs *regs)
|
|
+{
|
|
+ return false;
|
|
+}
|
|
+
|
|
+static inline void dsemul_mm_cleanup(struct mm_struct *mm)
|
|
+{
|
|
+
|
|
+}
|
|
+
|
|
+#endif
|
|
|
|
#endif /* __MIPS_ASM_DSEMUL_H__ */
|