[PATCH v3 8/8] powerpc/signal64: Rewrite rt_sigreturn() to minimise uaccess switches
flat view
STALE2089d
SUPERSEDED
From: Christopher M. Riedl <hidden>
Date: 2021-01-09 03:44:01
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Status: Superseded by v7 (posted 2021-02-27). [go to v7]
Revision v3 (7 revisions archived).
Revisions (7)
From: Daniel Axtens <redacted>
Add uaccess blocks and use the 'unsafe' versions of functions doing user
access where possible to reduce the number of times uaccess has to be
opened/closed.
Signed-off-by: Daniel Axtens <redacted>
Co-developed-by: Christopher M. Riedl <redacted>
Signed-off-by: Christopher M. Riedl <redacted>
---
arch/powerpc/kernel/signal_64.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 7e62d62ef482..1b1e39663999 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c@@ -784,8 +784,11 @@ SYSCALL_DEFINE0(rt_sigreturn) regs->msr &= ~MSR_TS_MASK; #endif - if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) + if (!user_read_access_begin(uc, sizeof(*uc))) goto badframe; + + unsafe_get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR], badframe_block); + if (MSR_TM_ACTIVE(msr)) { #ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* We recheckpoint on return. */
@@ -793,10 +796,12 @@ SYSCALL_DEFINE0(rt_sigreturn) /* Trying to start TM on non TM system */ if (!cpu_has_feature(CPU_FTR_TM)) - goto badframe; + goto badframe_block; + + unsafe_get_user(uc_transact, &uc->uc_link, badframe_block); + + user_read_access_end(); - if (__get_user(uc_transact, &uc->uc_link)) - goto badframe; if (restore_tm_sigcontexts(current, &uc->uc_mcontext, &uc_transact->uc_mcontext)) goto badframe;
@@ -815,12 +820,9 @@ SYSCALL_DEFINE0(rt_sigreturn) * causing a TM bad thing. */ current->thread.regs->msr &= ~MSR_TS_MASK; - if (!user_read_access_begin(uc, sizeof(*uc))) - return -EFAULT; - if (__unsafe_restore_sigcontext(current, NULL, 1, &uc->uc_mcontext)) { - user_read_access_end(); - goto badframe; - } + unsafe_restore_sigcontext(current, NULL, 1, &uc->uc_mcontext, + badframe_block); + user_read_access_end(); }
@@ -830,6 +832,8 @@ SYSCALL_DEFINE0(rt_sigreturn) set_thread_flag(TIF_RESTOREALL); return 0; +badframe_block: + user_read_access_end(); badframe: signal_fault(current, regs, "rt_sigreturn", uc);
--
2.26.1