diff options
| author | Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> | 2014-12-03 15:47:03 +0000 |
|---|---|---|
| committer | Markos Chandras <markos.chandras@imgtec.com> | 2015-02-17 15:37:37 +0000 |
| commit | b0a668fb2038d846a466c7a16a358d874002b697 (patch) | |
| tree | 78e1a41109308a34e08dd552ddf6834f085d288c /arch/mips/kernel/traps.c | |
| parent | b55b9e271544a23ca23b7ca3a87baf6329fcb341 (diff) | |
MIPS: kernel: mips-r2-to-r6-emul: Add R2 emulator for MIPS R6
MIPS R6 removed quite a few R2 instructions. However, there
is plenty of <R6 userland code so we add an in-kernel emulator
so we can still be able to execute all R2 userland out there.
The emulator comes with a handy debugfs under /mips/ directory
(r2-emul-stats) to provide some basic statistics of the
instructions that are being emulated.
Below are some statistics from booting a minimal buildroot image:
Instruction Total BDslot
------------------------------
movs 236969 0
hilo 56686 0
muls 55279 0
divs 10941 0
dsps 0 0
bops 1 0
traps 0 0
fpus 0 0
loads 214981 17
stores 103364 0
llsc 56898 0
dsemul 150418 0
jr 370158
bltzl 43
bgezl 1594
bltzll 0
bgezll 0
bltzal 39
bgezal 39
beql 14503
bnel 138741
blezl 0
bgtzl 3988
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Diffstat (limited to 'arch/mips/kernel/traps.c')
| -rw-r--r-- | arch/mips/kernel/traps.c | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 6e9d8505e128..fc157322f609 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -46,6 +46,7 @@ #include <asm/fpu.h> #include <asm/fpu_emulator.h> #include <asm/idle.h> +#include <asm/mips-r2-to-r6-emul.h> #include <asm/mipsregs.h> #include <asm/mipsmtregs.h> #include <asm/module.h> @@ -837,7 +838,7 @@ out: exception_exit(prev_state); } -static void do_trap_or_bp(struct pt_regs *regs, unsigned int code, +void do_trap_or_bp(struct pt_regs *regs, unsigned int code, const char *str) { siginfo_t info; @@ -1027,7 +1028,32 @@ asmlinkage void do_ri(struct pt_regs *regs) unsigned int opcode = 0; int status = -1; + /* + * Avoid any kernel code. Just emulate the R2 instruction + * as quickly as possible. + */ + if (mipsr2_emulation && cpu_has_mips_r6 && + likely(user_mode(regs))) { + if (likely(get_user(opcode, epc) >= 0)) { + status = mipsr2_decoder(regs, opcode); + switch (status) { + case 0: + case SIGEMT: + return; + case SIGILL: + goto no_r2_instr; + default: + process_fpemu_return(status, + ¤t->thread.cp0_baduaddr); + return; + } + } + } + +no_r2_instr: + prev_state = exception_enter(); + if (notify_die(DIE_RI, "RI Fault", regs, 0, regs_to_trapnr(regs), SIGILL) == NOTIFY_STOP) goto out; |