From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
patches@lists.linux.dev, Kyle Huey <me@kylehuey.com>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: [PATCH 5.15 06/10] x86/fpu: Emulate XRSTORs behavior if the xfeatures PKRU bit is not set
Date: Thu, 12 Jan 2023 14:56:43 +0100 [thread overview]
Message-ID: <20230112135326.931667008@linuxfoundation.org> (raw)
In-Reply-To: <20230112135326.689857506@linuxfoundation.org>
From: Kyle Huey <me@kylehuey.com>
commit d7e5aceace514a2b1b3ca3dc44f93f1704766ca7 upstream
The hardware XRSTOR instruction resets the PKRU register to its hardware
init value (namely 0) if the PKRU bit is not set in the xfeatures mask.
Emulating that here restores the pre-5.14 behavior for PTRACE_SET_REGSET
with NT_X86_XSTATE, and makes sigreturn (which still uses XRSTOR) and
behave identically.
Fixes: e84ba47e313d ("x86/fpu: Hook up PKRU into ptrace()")
Signed-off-by: Kyle Huey <me@kylehuey.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20221115230932.7126-6-khuey%40kylehuey.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/fpu/xstate.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1168,7 +1168,8 @@ static int copy_uabi_to_xstate(struct xr
xpkru = __raw_xsave_addr(xsave, XFEATURE_PKRU);
*pkru = xpkru->pkru;
- }
+ } else
+ *pkru = 0;
/*
* The state that came in from userspace was user-state only.
next prev parent reply other threads:[~2023-01-12 13:57 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-12 13:56 [PATCH 5.15 00/10] 5.15.88-rc1 review Greg Kroah-Hartman
2023-01-12 13:56 ` [PATCH 5.15 01/10] parisc: Align parisc MADV_XXX constants with all other architectures Greg Kroah-Hartman
2023-01-12 13:56 ` [PATCH 5.15 02/10] x86/fpu: Take task_struct* in copy_sigframe_from_user_to_xstate() Greg Kroah-Hartman
2023-01-12 13:56 ` [PATCH 5.15 03/10] x86/fpu: Add a pkru argument to copy_uabi_from_kernel_to_xstate() Greg Kroah-Hartman
2023-01-12 13:56 ` [PATCH 5.15 04/10] x86/fpu: Add a pkru argument to copy_uabi_to_xstate() Greg Kroah-Hartman
2023-01-12 13:56 ` [PATCH 5.15 05/10] x86/fpu: Allow PKRU to be (once again) written by ptrace Greg Kroah-Hartman
2023-01-12 13:56 ` Greg Kroah-Hartman [this message]
2023-01-12 13:56 ` [PATCH 5.15 07/10] selftests/vm/pkeys: Add a regression test for setting PKRU through ptrace Greg Kroah-Hartman
2023-01-12 13:56 ` [PATCH 5.15 08/10] serial: fixup backport of "serial: Deassert Transmit Enable on probe in driver-specific way" Greg Kroah-Hartman
2023-01-12 13:56 ` [PATCH 5.15 09/10] net: sched: disallow noqueue for qdisc classes Greg Kroah-Hartman
2023-01-12 13:56 ` [PATCH 5.15 10/10] net/ulp: prevent ULP without clone op from entering the LISTEN status Greg Kroah-Hartman
2023-01-12 20:52 ` [PATCH 5.15 00/10] 5.15.88-rc1 review Florian Fainelli
2023-01-13 0:28 ` Shuah Khan
2023-01-13 1:36 ` Kelsey Steele
2023-01-13 4:15 ` Bagas Sanjaya
2023-01-13 5:50 ` Guenter Roeck
2023-01-13 12:32 ` Sudip Mukherjee
2023-01-13 13:19 ` Jon Hunter
2023-01-13 17:42 ` Naresh Kamboju
2023-01-13 18:00 ` Allen Pais
2023-01-13 23:39 ` Ron Economos
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