Messages in this thread Patch in this message | | | From | Christophe Leroy <> | Subject | [PATCH v2 03/15] powerpc/align: Convert emulate_spe() to user_access_begin | Date | Wed, 10 Mar 2021 17:46:42 +0000 (UTC) |
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This patch converts emulate_spe() to using user_access_being logic.
Since commit 662bbcb2747c ("mm, sched: Allow uaccess in atomic with pagefault_disable()"), might_fault() doesn't fire when called from sections where pagefaults are disabled, which must be the case when using _inatomic variants of __get_user and __put_user. So the might_fault() in user_access_begin() is not a problem.
There was a verification of user_mode() together with the access_ok(), but the function returns in case !user_mode() immediately after the access_ok() verification, so removing that test has no effect.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- arch/powerpc/kernel/align.c | 61 ++++++++++++++++++++----------------- 1 file changed, 33 insertions(+), 28 deletions(-)
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c index c7797eb958c7..c4d7b445b459 100644 --- a/arch/powerpc/kernel/align.c +++ b/arch/powerpc/kernel/align.c @@ -107,7 +107,6 @@ static struct aligninfo spe_aligninfo[32] = { static int emulate_spe(struct pt_regs *regs, unsigned int reg, struct ppc_inst ppc_instr) { - int ret; union { u64 ll; u32 w[2]; @@ -127,11 +126,6 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg, nb = spe_aligninfo[instr].len; flags = spe_aligninfo[instr].flags; - /* Verify the address of the operand */ - if (unlikely(user_mode(regs) && - !access_ok(addr, nb))) - return -EFAULT; - /* userland only */ if (unlikely(!user_mode(regs))) return 0; @@ -169,26 +163,27 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg, } } else { temp.ll = data.ll = 0; - ret = 0; p = addr; + if (!user_read_access_begin(addr, nb)) + return -EFAULT; + switch (nb) { case 8: - ret |= __get_user_inatomic(temp.v[0], p++); - ret |= __get_user_inatomic(temp.v[1], p++); - ret |= __get_user_inatomic(temp.v[2], p++); - ret |= __get_user_inatomic(temp.v[3], p++); + unsafe_get_user(temp.v[0], p++, Efault_read); + unsafe_get_user(temp.v[1], p++, Efault_read); + unsafe_get_user(temp.v[2], p++, Efault_read); + unsafe_get_user(temp.v[3], p++, Efault_read); fallthrough; case 4: - ret |= __get_user_inatomic(temp.v[4], p++); - ret |= __get_user_inatomic(temp.v[5], p++); + unsafe_get_user(temp.v[4], p++, Efault_read); + unsafe_get_user(temp.v[5], p++, Efault_read); fallthrough; case 2: - ret |= __get_user_inatomic(temp.v[6], p++); - ret |= __get_user_inatomic(temp.v[7], p++); - if (unlikely(ret)) - return -EFAULT; + unsafe_get_user(temp.v[6], p++, Efault_read); + unsafe_get_user(temp.v[7], p++, Efault_read); } + user_read_access_end(); switch (instr) { case EVLDD: @@ -255,31 +250,41 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg, /* Store result to memory or update registers */ if (flags & ST) { - ret = 0; p = addr; + + if (!user_read_access_begin(addr, nb)) + return -EFAULT; + switch (nb) { case 8: - ret |= __put_user_inatomic(data.v[0], p++); - ret |= __put_user_inatomic(data.v[1], p++); - ret |= __put_user_inatomic(data.v[2], p++); - ret |= __put_user_inatomic(data.v[3], p++); + unsafe_put_user(data.v[0], p++, Efault_write); + unsafe_put_user(data.v[1], p++, Efault_write); + unsafe_put_user(data.v[2], p++, Efault_write); + unsafe_put_user(data.v[3], p++, Efault_write); fallthrough; case 4: - ret |= __put_user_inatomic(data.v[4], p++); - ret |= __put_user_inatomic(data.v[5], p++); + unsafe_put_user(data.v[4], p++, Efault_write); + unsafe_put_user(data.v[5], p++, Efault_write); fallthrough; case 2: - ret |= __put_user_inatomic(data.v[6], p++); - ret |= __put_user_inatomic(data.v[7], p++); + unsafe_put_user(data.v[6], p++, Efault_write); + unsafe_put_user(data.v[7], p++, Efault_write); } - if (unlikely(ret)) - return -EFAULT; + user_write_access_end(); } else { *evr = data.w[0]; regs->gpr[reg] = data.w[1]; } return 1; + +Efault_read: + user_read_access_end(); + return -EFAULT; + +Efault_write: + user_write_access_end(); + return -EFAULT; } #endif /* CONFIG_SPE */ -- 2.25.0
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