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um: series of __get_user() is costly in sigframe handling

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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>
This commit is contained in:
Al Viro 2011-08-18 20:00:49 +01:00 committed by Richard Weinberger
parent 3d72210bdc
commit a955bd611d
2 changed files with 77 additions and 83 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
arch/um/sys-i386/signal.c
View File

@ -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(&regs->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 = &current->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);

112
arch/um/sys-x86_64/signal.c
View File

@ -16,41 +16,39 @@
static int copy_sc_from_user(struct pt_regs *regs,
struct sigcontext __user *from)
{
struct sigcontext sc;
struct user_i387_struct fp;
void __user *buf;
int err = 0;
int err;
#define GETREG(regs, regno, sc, regname) \
__get_user((regs)->regs.gp[(regno) / sizeof(unsigned long)], \
&(sc)->regname)
err |= GETREG(regs, R8, from, r8);
err |= GETREG(regs, R9, from, r9);
err |= GETREG(regs, R10, from, r10);
err |= GETREG(regs, R11, from, r11);
err |= GETREG(regs, R12, from, r12);
err |= GETREG(regs, R13, from, r13);
err |= GETREG(regs, R14, from, r14);
err |= GETREG(regs, R15, from, r15);
err |= GETREG(regs, RDI, from, di);
err |= GETREG(regs, RSI, from, si);
err |= GETREG(regs, RBP, from, bp);
err |= GETREG(regs, RBX, from, bx);
err |= GETREG(regs, RDX, from, dx);
err |= GETREG(regs, RAX, from, ax);
err |= GETREG(regs, RCX, from, cx);
err |= GETREG(regs, RSP, from, sp);
err |= GETREG(regs, RIP, from, ip);
err |= GETREG(regs, EFLAGS, from, flags);
err |= GETREG(regs, CS, from, cs);
err = copy_from_user(&sc, from, sizeof(sc));
if (err)
return 1;
return err;
#define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname
GETREG(R8, r8);
GETREG(R9, r9);
GETREG(R10, r10);
GETREG(R11, r11);
GETREG(R12, r12);
GETREG(R13, r13);
GETREG(R14, r14);
GETREG(R15, r15);
GETREG(RDI, di);
GETREG(RSI, si);
GETREG(RBP, bp);
GETREG(RBX, bx);
GETREG(RDX, dx);
GETREG(RAX, ax);
GETREG(RCX, cx);
GETREG(SP, sp);
GETREG(IP, ip);
GETREG(EFLAGS, flags);
GETREG(CS, cs);
#undef GETREG
err = __get_user(buf, &from->fpstate);
if (err)
return 1;
buf = sc.fpstate;
err = copy_from_user(&fp, buf, sizeof(struct user_i387_struct));
if (err)
@ -73,48 +71,46 @@ static int copy_sc_to_user(struct sigcontext __user *to,
unsigned long mask, unsigned long sp)
{
struct faultinfo * fi = &current->thread.arch.faultinfo;
struct sigcontext sc;
struct user_i387_struct fp;
int err = 0;
memset(&sc, 0, sizeof(struct sigcontext));
err |= __put_user(0, &to->gs);
err |= __put_user(0, &to->fs);
#define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno]
#define PUTREG(regs, regno, sc, regname) \
__put_user((regs)->regs.gp[(regno) / sizeof(unsigned long)], \
&(sc)->regname)
err |= PUTREG(regs, RDI, to, di);
err |= PUTREG(regs, RSI, to, si);
err |= PUTREG(regs, RBP, to, bp);
PUTREG(RDI, di);
PUTREG(RSI, si);
PUTREG(RBP, bp);
/*
* Must use original RSP, which is passed in, rather than what's in
* the pt_regs, because that's already been updated to point at the
* signal frame.
*/
err |= __put_user(sp, &to->sp);
err |= PUTREG(regs, RBX, to, bx);
err |= PUTREG(regs, RDX, to, dx);
err |= PUTREG(regs, RCX, to, cx);
err |= PUTREG(regs, RAX, to, ax);
err |= PUTREG(regs, R8, to, r8);
err |= PUTREG(regs, R9, to, r9);
err |= PUTREG(regs, R10, to, r10);
err |= PUTREG(regs, R11, to, r11);
err |= PUTREG(regs, R12, to, r12);
err |= PUTREG(regs, R13, to, r13);
err |= PUTREG(regs, R14, to, r14);
err |= PUTREG(regs, R15, to, r15);
err |= PUTREG(regs, CS, to, cs); /* XXX x86_64 doesn't do this */
sc.sp = sp;
PUTREG(RBX, bx);
PUTREG(RDX, dx);
PUTREG(RCX, cx);
PUTREG(RAX, ax);
PUTREG(R8, r8);
PUTREG(R9, r9);
PUTREG(R10, r10);
PUTREG(R11, r11);
PUTREG(R12, r12);
PUTREG(R13, r13);
PUTREG(R14, r14);
PUTREG(R15, r15);
PUTREG(CS, cs); /* XXX x86_64 doesn't do this */
err |= __put_user(fi->cr2, &to->cr2);
err |= __put_user(fi->error_code, &to->err);
err |= __put_user(fi->trap_no, &to->trapno);
sc.cr2 = fi->cr2;
sc.err = fi->error_code;
sc.trapno = fi->trap_no;
err |= PUTREG(regs, RIP, to, ip);
err |= PUTREG(regs, EFLAGS, to, flags);
PUTREG(IP, ip);
PUTREG(EFLAGS, flags);
#undef PUTREG
err |= __put_user(mask, &to->oldmask);
sc.oldmask = mask;
err = copy_to_user(to, &sc, sizeof(struct sigcontext));
if (err)
return 1;