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author | Al Viro <viro@ftp.linux.org.uk> | 2011-08-18 19:00:49 (GMT) |
---|---|---|
committer | Richard Weinberger <richard@nod.at> | 2011-11-02 13:14:42 (GMT) |
commit | a955bd611d6426bf7b61cab01f8ddee9cc169736 (patch) | |
tree | f2f42f996bbb757e6f8ebd805fe1e975893dcc32 /arch/um/sys-i386/signal.c | |
parent | 3d72210bdc1ef67b72ffbd3e74873cae7287f2c6 (diff) | |
download | linux-fsl-qoriq-a955bd611d6426bf7b61cab01f8ddee9cc169736.tar.xz |
um: series of __get_user() is costly in sigframe handling
It's not x86, where __get_user() is a single dereference; here it's
a single ptrace(2) call in host, which obviously costs a lot more.
IOW, it's cheaper to do copy_{to,from}_user() once than bother with
fields one by one...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um/sys-i386/signal.c')
-rw-r--r-- | arch/um/sys-i386/signal.c | 48 |
1 files changed, 23 insertions, 25 deletions
diff --git a/arch/um/sys-i386/signal.c b/arch/um/sys-i386/signal.c index b87195b..bcbfb0d 100644 --- a/arch/um/sys-i386/signal.c +++ b/arch/um/sys-i386/signal.c @@ -10,28 +10,6 @@ #include "frame_kern.h" #include "skas.h" -static void copy_sc(struct uml_pt_regs *regs, void *from) -{ - struct sigcontext *sc = from; - - REGS_GS(regs->gp) = sc->gs; - REGS_FS(regs->gp) = sc->fs; - REGS_ES(regs->gp) = sc->es; - REGS_DS(regs->gp) = sc->ds; - REGS_EDI(regs->gp) = sc->di; - REGS_ESI(regs->gp) = sc->si; - REGS_EBP(regs->gp) = sc->bp; - REGS_SP(regs->gp) = sc->sp; - REGS_EBX(regs->gp) = sc->bx; - REGS_EDX(regs->gp) = sc->dx; - REGS_ECX(regs->gp) = sc->cx; - REGS_EAX(regs->gp) = sc->ax; - REGS_IP(regs->gp) = sc->ip; - REGS_CS(regs->gp) = sc->cs; - REGS_EFLAGS(regs->gp) = sc->flags; - REGS_SS(regs->gp) = sc->ss; -} - /* * FPU tag word conversions. */ @@ -175,7 +153,27 @@ static int copy_sc_from_user(struct pt_regs *regs, return err; pid = userspace_pid[current_thread_info()->cpu]; - copy_sc(®s->regs, &sc); + +#define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname + + GETREG(GS, gs); + GETREG(FS, fs); + GETREG(ES, es); + GETREG(DS, ds); + GETREG(EDI, di); + GETREG(ESI, si); + GETREG(EBP, bp); + GETREG(SP, sp); + GETREG(EBX, bx); + GETREG(EDX, dx); + GETREG(ECX, cx); + GETREG(EAX, ax); + GETREG(IP, ip); + GETREG(CS, cs); + GETREG(EFLAGS, flags); + GETREG(SS, ss); + +#undef GETREG if (have_fpx_regs) { struct user_fxsr_struct fpx; @@ -196,8 +194,7 @@ static int copy_sc_from_user(struct pt_regs *regs, -err); return 1; } - } - else { + } else { struct user_i387_struct fp; err = copy_from_user(&fp, sc.fpstate, @@ -224,6 +221,7 @@ static int copy_sc_to_user(struct sigcontext __user *to, struct sigcontext sc; struct faultinfo * fi = ¤t->thread.arch.faultinfo; int err, pid; + memset(&sc, 0, sizeof(struct sigcontext)); sc.gs = REGS_GS(regs->regs.gp); sc.fs = REGS_FS(regs->regs.gp); |