openwrt/target/linux/generic/pending-4.19/304-mips_disable_fpu.patch
Hauke Mehrtens 9261e7447e kernel: Make the patches apply on top of 4.19
This makes the patches which were just copied in the previous commit
apply on top of kernel 4.19.

The patches in the backports-4.19 folder were checked if they are really
in kernel 4.19 based on the title and only removed if they were found in
the upstream kernel.

The following additional patches form the pending folder went into
upstream Linux 4.19:
pending-4.19/171-usb-dwc2-Fix-inefficient-copy-of-unaligned-buffers.patch
pending-4.19/190-2-5-e1000e-Fix-wrong-comment-related-to-link-detection.patch
pending-4.19/478-mtd-spi-nor-Add-support-for-XM25QH64A-and-XM25QH128A.patch
pending-4.19/479-mtd-spi-nor-add-eon-en25qh32.patch
pending-4.19/950-tty-serial-exar-generalize-rs485-setup.patch
pending-4.19/340-MIPS-mm-remove-mips_dma_mapping_error.patch

Bigger changes were introduced to the m25p80 spi nor driver, as far as I
saw it in the new code, it now has the functionality provided in this
patch:
pending-4.19/450-mtd-m25p80-allow-fallback-from-spi_flash_read-to-reg.patch

Part of this patch went upstream independent of OpenWrt:
hack-4.19/220-gc_sections.patch
This patch was reworked to match the changes done upstream.

The MIPS DMA API changed a lot, this patch was rewritten to match the
new DMA handling:
pending-4.19/341-MIPS-mm-remove-no-op-dma_map_ops-where-possible.patch

I did bigger manual changes to the following patches and I am not 100% sure if they are all correct:
pending-4.19/0931-w1-gpio-fix-problem-with-platfom-data-in-w1-gpio.patch
pending-4.19/411-mtd-partial_eraseblock_write.patch
pending-4.19/600-netfilter_conntrack_flush.patch
pending-4.19/611-netfilter_match_bypass_default_table.patch
pending-4.19/670-ipv6-allow-rejecting-with-source-address-failed-policy.patch
hack-4.19/211-host_tools_portability.patch
hack-4.19/221-module_exports.patch
hack-4.19/321-powerpc_crtsavres_prereq.patch
hack-4.19/902-debloat_proc.patch

This is based on patchset from Marko Ratkaj <marko.ratkaj@sartura.hr>

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
2018-12-15 14:28:48 +01:00

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
@@ -2889,6 +2889,20 @@ 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
@@ -322,7 +322,7 @@ 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__ */