From 64243c2a945640392b59fe1dc66c30ee1ca04170 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Mon, 27 Jul 2015 12:58:16 -0700 Subject: [PATCH] MIPS: Move FP usage checks into protected_{save, restore}_fp_context In preparation for sharing protected_{save,restore}_fp_context with compat ABIs, move the FP usage checks into said functions. This will both enable that code to be shared, and allow for extensions of it in further patches to also be shared. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Cc: Guenter Roeck Cc: Matthew Fortune Cc: Michael Ellerman Cc: linux-kernel@vger.kernel.org Cc: Richard Weinberger Cc: Andy Lutomirski Cc: Maciej W. Rozycki Patchwork: https://patchwork.linux-mips.org/patch/10790/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/signal.c | 73 ++++++++++++++++++--------------------- 1 file changed, 34 insertions(+), 39 deletions(-) diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c index 10f7dbc989c4..9c42c500134e 100644 --- a/arch/mips/kernel/signal.c +++ b/arch/mips/kernel/signal.c @@ -127,8 +127,15 @@ static int protected_save_fp_context(void __user *sc) struct mips_abi *abi = current->thread.abi; uint64_t __user *fpregs = sc + abi->off_sc_fpregs; uint32_t __user *csr = sc + abi->off_sc_fpc_csr; + uint32_t __user *used_math = sc + abi->off_sc_used_math; + unsigned int used; int err; + used = !!used_math(); + err = __put_user(used, used_math); + if (err || !used) + return err; + /* * EVA does not have userland equivalents of ldc1 or sdc1, so * save to the kernel FP context & copy that to userland below. @@ -163,7 +170,25 @@ static int protected_restore_fp_context(void __user *sc) struct mips_abi *abi = current->thread.abi; uint64_t __user *fpregs = sc + abi->off_sc_fpregs; uint32_t __user *csr = sc + abi->off_sc_fpc_csr; - int err, tmp __maybe_unused; + uint32_t __user *used_math = sc + abi->off_sc_used_math; + unsigned int used; + int err, sig, tmp __maybe_unused; + + err = __get_user(used, used_math); + conditional_used_math(used); + + /* + * The signal handler may have used FPU; give it up if the program + * doesn't want it following sigreturn. + */ + if (err || !used) { + lose_fpu(0); + return err; + } + + err = sig = fpcsr_pending(csr); + if (err < 0) + return err; /* * EVA does not have userland equivalents of ldc1 or sdc1, so we @@ -192,14 +217,13 @@ static int protected_restore_fp_context(void __user *sc) break; /* really bad sigcontext */ } - return err; + return err ?: sig; } int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { int err = 0; int i; - unsigned int used_math; err |= __put_user(regs->cp0_epc, &sc->sc_pc); @@ -222,16 +246,13 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp); } - used_math = !!used_math(); - err |= __put_user(used_math, &sc->sc_used_math); - if (used_math) { - /* - * Save FPU state to signal context. Signal handler - * will "inherit" current FPU state. - */ - err |= protected_save_fp_context(sc); - } + /* + * Save FPU state to signal context. Signal handler + * will "inherit" current FPU state. + */ + err |= protected_save_fp_context(sc); + return err; } @@ -254,22 +275,8 @@ int fpcsr_pending(unsigned int __user *fpcsr) return err ?: sig; } -static int -check_and_restore_fp_context(void __user *sc) -{ - struct mips_abi *abi = current->thread.abi; - int err, sig; - - err = sig = fpcsr_pending(sc + abi->off_sc_fpc_csr); - if (err > 0) - err = 0; - err |= protected_restore_fp_context(sc); - return err ?: sig; -} - int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { - unsigned int used_math; unsigned long treg; int err = 0; int i; @@ -297,19 +304,7 @@ int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) for (i = 1; i < 32; i++) err |= __get_user(regs->regs[i], &sc->sc_regs[i]); - err |= __get_user(used_math, &sc->sc_used_math); - conditional_used_math(used_math); - - if (used_math) { - /* restore fpu context if we have used it before */ - if (!err) - err = check_and_restore_fp_context(sc); - } else { - /* signal handler may have used FPU. Give it up. */ - lose_fpu(0); - } - - return err; + return err ?: protected_restore_fp_context(sc); } void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, -- 2.30.2