linux-stable.git/arch/arm64/kernel, branch linux-3.16.y Linux kernel stable tree arm64: debug: Ensure debug handlers check triggering exception level 2020-01-11T02:04:59+00:00 Will Deacon will.deacon@arm.com 2019-03-01T13:28:01+00:00 551da7ca4fa4e7356fc921077b0f8419280a34f4 commit 6bd288569b50bc89fa5513031086746968f585cb upstream. Debug exception handlers may be called for exceptions generated both by user and kernel code. In many cases, this is checked explicitly, but in other cases things either happen to work by happy accident or they go slightly wrong. For example, executing 'brk #4' from userspace will enter the kprobes code and be ignored, but the instruction will be retried forever in userspace instead of delivering a SIGTRAP. Fix this issue in the most stable-friendly fashion by simply adding explicit checks of the triggering exception level to all of our debug exception handlers. Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 6bd288569b50bc89fa5513031086746968f585cb upstream.

Debug exception handlers may be called for exceptions generated both by
user and kernel code. In many cases, this is checked explicitly, but
in other cases things either happen to work by happy accident or they
go slightly wrong. For example, executing 'brk #4' from userspace will
enter the kprobes code and be ignored, but the instruction will be
retried forever in userspace instead of delivering a SIGTRAP.

Fix this issue in the most stable-friendly fashion by simply adding
explicit checks of the triggering exception level to all of our debug
exception handlers.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
arm64/kernel: fix incorrect EL0 check in inv_entry macro 2020-01-11T02:04:54+00:00 Ard Biesheuvel ard.biesheuvel@linaro.org 2016-03-18T09:58:09+00:00 3865feeeed4502f7281041b9390b6d06750d9605 commit b660950c60a7278f9d8deb7c32a162031207c758 upstream. The implementation of macro inv_entry refers to its 'el' argument without the required leading backslash, which results in an undefined symbol 'el' to be passed into the kernel_entry macro rather than the index of the exception level as intended. This undefined symbol strangely enough does not result in build failures, although it is visible in vmlinux: $ nm -n vmlinux |head U el 0000000000000000 A _kernel_flags_le_hi32 0000000000000000 A _kernel_offset_le_hi32 0000000000000000 A _kernel_size_le_hi32 000000000000000a A _kernel_flags_le_lo32 ..... However, it does result in incorrect code being generated for invalid exceptions taken from EL0, since the argument check in kernel_entry assumes EL1 if its argument does not equal '0'. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit b660950c60a7278f9d8deb7c32a162031207c758 upstream.

The implementation of macro inv_entry refers to its 'el' argument without
the required leading backslash, which results in an undefined symbol
'el' to be passed into the kernel_entry macro rather than the index of
the exception level as intended.

This undefined symbol strangely enough does not result in build failures,
although it is visible in vmlinux:

     $ nm -n vmlinux |head
                      U el
     0000000000000000 A _kernel_flags_le_hi32
     0000000000000000 A _kernel_offset_le_hi32
     0000000000000000 A _kernel_size_le_hi32
     000000000000000a A _kernel_flags_le_lo32
     .....

However, it does result in incorrect code being generated for invalid
exceptions taken from EL0, since the argument check in kernel_entry
assumes EL1 if its argument does not equal '0'.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
arm64: traps: disable irq in die() 2020-01-11T02:04:48+00:00 Qiao Zhou qiaozhou@asrmicro.com 2017-07-07T09:29:34+00:00 ec4efc4c5fbdd9ad303a9b078b4d72f5a4c7844b commit 6f44a0bacb79a03972c83759711832b382b1b8ac upstream. In current die(), the irq is disabled for __die() handle, not including the possible panic() handling. Since the log in __die() can take several hundreds ms, new irq might come and interrupt current die(). If the process calling die() holds some critical resource, and some other process scheduled later also needs it, then it would deadlock. The first panic will not be executed. So here disable irq for the whole flow of die(). Signed-off-by: Qiao Zhou <qiaozhou@asrmicro.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 6f44a0bacb79a03972c83759711832b382b1b8ac upstream.

In current die(), the irq is disabled for __die() handle, not
including the possible panic() handling. Since the log in __die()
can take several hundreds ms, new irq might come and interrupt
current die().

If the process calling die() holds some critical resource, and some
other process scheduled later also needs it, then it would deadlock.
The first panic will not be executed.

So here disable irq for the whole flow of die().

Signed-off-by: Qiao Zhou <qiaozhou@asrmicro.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
arm64: compat: Allow single-byte watchpoints on all addresses 2019-11-22T15:57:08+00:00 Will Deacon will@kernel.org 2019-07-29T10:06:17+00:00 a91e913e8f7aba2b485161379f5f9b63fce373c3 commit 849adec41203ac5837c40c2d7e08490ffdef3c2c upstream. Commit d968d2b801d8 ("ARM: 7497/1: hw_breakpoint: allow single-byte watchpoints on all addresses") changed the validation requirements for hardware watchpoints on arch/arm/. Update our compat layer to implement the same relaxation. Signed-off-by: Will Deacon <will@kernel.org> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 849adec41203ac5837c40c2d7e08490ffdef3c2c upstream.

Commit d968d2b801d8 ("ARM: 7497/1: hw_breakpoint: allow single-byte
watchpoints on all addresses") changed the validation requirements for
hardware watchpoints on arch/arm/. Update our compat layer to implement
the same relaxation.

Signed-off-by: Will Deacon <will@kernel.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
jump_label: Rename JUMP_LABEL_{EN,DIS}ABLE to JUMP_LABEL_{JMP,NOP} 2019-05-22T22:15:03+00:00 Peter Zijlstra peterz@infradead.org 2015-07-24T12:45:44+00:00 1637ff670ad30d13d430b71058939f399f5ad8bd commit 76b235c6bcb16062d663e2ee96db0b69f2e6bc14 upstream. Since we've already stepped away from ENABLE is a JMP and DISABLE is a NOP with the branch_default bits, and are going to make it even worse, rename it to make it all clearer. This way we don't mix multiple levels of logic attributes, but have a plain 'physical' name for what the current instruction patching status of a jump label is. This is a first step in removing the naming confusion that has led to a stream of avoidable bugs such as: a833581e372a ("x86, perf: Fix static_key bug in load_mm_cr4()") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org [ Beefed up the changelog. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 76b235c6bcb16062d663e2ee96db0b69f2e6bc14 upstream.

Since we've already stepped away from ENABLE is a JMP and DISABLE is a
NOP with the branch_default bits, and are going to make it even worse,
rename it to make it all clearer.

This way we don't mix multiple levels of logic attributes, but have a
plain 'physical' name for what the current instruction patching status
of a jump label is.

This is a first step in removing the naming confusion that has led to
a stream of avoidable bugs such as:

  a833581e372a ("x86, perf: Fix static_key bug in load_mm_cr4()")

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
[ Beefed up the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
arm64: Use get_signal() signal_setup_done() 2019-05-02T20:41:41+00:00 Richard Weinberger richard@nod.at 2013-10-06T20:52:44+00:00 57925c615b3b75d49507c30517c6969707276c6d commit 00554fa4f80279db92f82c4f52c8ae72711f173e upstream. Use the more generic functions get_signal() signal_setup_done() for signal delivery. Signed-off-by: Richard Weinberger <richard@nod.at> [bwh: Backported to 3.16 as dependency of commit 35634ffa1751 "signal: Always notice exiting tasks"] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 00554fa4f80279db92f82c4f52c8ae72711f173e upstream.

Use the more generic functions get_signal() signal_setup_done()
for signal delivery.

Signed-off-by: Richard Weinberger <richard@nod.at>
[bwh: Backported to 3.16 as dependency of commit 35634ffa1751
 "signal: Always notice exiting tasks"]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
arm64: __show_regs: Only resolve kernel symbols when running at EL1 2018-06-16T21:22:21+00:00 Will Deacon will.deacon@arm.com 2018-02-19T16:46:57+00:00 18ba80533558af0cb186ccb71022fabfa9604ffe commit a06f818a70de21b4b3b4186816094208fc7accf9 upstream. __show_regs pretty prints PC and LR by attempting to map them to kernel function names to improve the utility of crash reports. Unfortunately, this mapping is applied even when the pt_regs corresponds to user mode, resulting in a KASLR oracle. Avoid this issue by only looking up the function symbols when the register state indicates that we're actually running at EL1. Reported-by: NCSC Security <security@ncsc.gov.uk> Signed-off-by: Will Deacon <will.deacon@arm.com> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit a06f818a70de21b4b3b4186816094208fc7accf9 upstream.

__show_regs pretty prints PC and LR by attempting to map them to kernel
function names to improve the utility of crash reports. Unfortunately,
this mapping is applied even when the pt_regs corresponds to user mode,
resulting in a KASLR oracle.

Avoid this issue by only looking up the function symbols when the register
state indicates that we're actually running at EL1.

Reported-by: NCSC Security <security@ncsc.gov.uk>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
arm64: Remove unimplemented syscall log message 2018-06-16T21:22:21+00:00 Michael Weiser michael.weiser@gmx.de 2018-02-01T22:13:36+00:00 db95024d392a6b65962b4f68c3fcca6bb67299b0 commit 1962682d2b2fbe6cfa995a85c53c069fadda473e upstream. Stop printing a (ratelimited) kernel message for each instance of an unimplemented syscall being called. Userland making an unimplemented syscall is not necessarily misbehaviour and to be expected with a current userland running on an older kernel. Also, the current message looks scary to users but does not actually indicate a real problem nor help them narrow down the cause. Just rely on sys_ni_syscall() to return -ENOSYS. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Michael Weiser <michael.weiser@gmx.de> Signed-off-by: Will Deacon <will.deacon@arm.com> [bwh: Backported to 3.16: Deleted code was slightly different] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 1962682d2b2fbe6cfa995a85c53c069fadda473e upstream.

Stop printing a (ratelimited) kernel message for each instance of an
unimplemented syscall being called. Userland making an unimplemented
syscall is not necessarily misbehaviour and to be expected with a
current userland running on an older kernel. Also, the current message
looks scary to users but does not actually indicate a real problem nor
help them narrow down the cause. Just rely on sys_ni_syscall() to return
-ENOSYS.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Michael Weiser <michael.weiser@gmx.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[bwh: Backported to 3.16: Deleted code was slightly different]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
arm64: Disable unhandled signal log messages by default 2018-06-16T21:22:21+00:00 Michael Weiser michael.weiser@gmx.de 2018-02-01T22:13:38+00:00 92ead7477a728c5bdf9f5ae6e9b58530bd984e1e commit 5ee39a71fd89ab7240c5339d04161c44a8e03269 upstream. aarch64 unhandled signal kernel messages are very verbose, suggesting them to be more of a debugging aid: sigsegv[33]: unhandled level 2 translation fault (11) at 0x00000000, esr 0x92000046, in sigsegv[400000+71000] CPU: 1 PID: 33 Comm: sigsegv Tainted: G W 4.15.0-rc3+ #3 Hardware name: linux,dummy-virt (DT) pstate: 60000000 (nZCv daif -PAN -UAO) pc : 0x4003f4 lr : 0x4006bc sp : 0000fffffe94a060 x29: 0000fffffe94a070 x28: 0000000000000000 x27: 0000000000000000 x26: 0000000000000000 x25: 0000000000000000 x24: 00000000004001b0 x23: 0000000000486ac8 x22: 00000000004001c8 x21: 0000000000000000 x20: 0000000000400be8 x19: 0000000000400b30 x18: 0000000000484728 x17: 000000000865ffc8 x16: 000000000000270f x15: 00000000000000b0 x14: 0000000000000002 x13: 0000000000000001 x12: 0000000000000000 x11: 0000000000000000 x10: 0008000020008008 x9 : 000000000000000f x8 : ffffffffffffffff x7 : 0004000000000000 x6 : ffffffffffffffff x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000004003e4 x2 : 0000fffffe94a1e8 x1 : 000000000000000a x0 : 0000000000000000 Disable them by default, so they can be enabled using /proc/sys/debug/exception-trace. Signed-off-by: Michael Weiser <michael.weiser@gmx.de> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 5ee39a71fd89ab7240c5339d04161c44a8e03269 upstream.

aarch64 unhandled signal kernel messages are very verbose, suggesting
them to be more of a debugging aid:

sigsegv[33]: unhandled level 2 translation fault (11) at 0x00000000, esr
0x92000046, in sigsegv[400000+71000]
CPU: 1 PID: 33 Comm: sigsegv Tainted: G        W        4.15.0-rc3+ #3
Hardware name: linux,dummy-virt (DT)
pstate: 60000000 (nZCv daif -PAN -UAO)
pc : 0x4003f4
lr : 0x4006bc
sp : 0000fffffe94a060
x29: 0000fffffe94a070 x28: 0000000000000000
x27: 0000000000000000 x26: 0000000000000000
x25: 0000000000000000 x24: 00000000004001b0
x23: 0000000000486ac8 x22: 00000000004001c8
x21: 0000000000000000 x20: 0000000000400be8
x19: 0000000000400b30 x18: 0000000000484728
x17: 000000000865ffc8 x16: 000000000000270f
x15: 00000000000000b0 x14: 0000000000000002
x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: 0008000020008008
x9 : 000000000000000f x8 : ffffffffffffffff
x7 : 0004000000000000 x6 : ffffffffffffffff
x5 : 0000000000000000 x4 : 0000000000000000
x3 : 00000000004003e4 x2 : 0000fffffe94a1e8
x1 : 000000000000000a x0 : 0000000000000000

Disable them by default, so they can be enabled using
/proc/sys/debug/exception-trace.

Signed-off-by: Michael Weiser <michael.weiser@gmx.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
arm64: do not use print_symbol() 2018-06-16T21:22:21+00:00 Sergey Senozhatsky sergey.senozhatsky.work@gmail.com 2017-12-11T12:50:14+00:00 0f61d6c3992a46f9b7eb52ec6c493bfebe342dcd commit 4ef7963843d3243260aa335dfb9cb2fede06aacf upstream. print_symbol() is a very old API that has been obsoleted by %pS format specifier in a normal printk() call. Replace print_symbol() with a direct printk("%pS") call. Link: http://lkml.kernel.org/r/20171211125025.2270-3-sergey.senozhatsky@gmail.com To: Andrew Morton <akpm@linux-foundation.org> To: Russell King <linux@armlinux.org.uk> To: Catalin Marinas <catalin.marinas@arm.com> To: Mark Salter <msalter@redhat.com> To: Tony Luck <tony.luck@intel.com> To: David Howells <dhowells@redhat.com> To: Yoshinori Sato <ysato@users.sourceforge.jp> To: Guan Xuetao <gxt@mprc.pku.edu.cn> To: Borislav Petkov <bp@alien8.de> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org> To: Thomas Gleixner <tglx@linutronix.de> To: Peter Zijlstra <peterz@infradead.org> To: Vineet Gupta <vgupta@synopsys.com> To: Fengguang Wu <fengguang.wu@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Petr Mladek <pmladek@suse.com> Cc: LKML <linux-kernel@vger.kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-ia64@vger.kernel.org Cc: linux-am33-list@redhat.com Cc: linux-sh@vger.kernel.org Cc: linux-edac@vger.kernel.org Cc: x86@kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> [pmladek@suse.com: updated commit message] Signed-off-by: Petr Mladek <pmladek@suse.com> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 4ef7963843d3243260aa335dfb9cb2fede06aacf upstream.

print_symbol() is a very old API that has been obsoleted by %pS format
specifier in a normal printk() call.

Replace print_symbol() with a direct printk("%pS") call.

Link: http://lkml.kernel.org/r/20171211125025.2270-3-sergey.senozhatsky@gmail.com
To: Andrew Morton <akpm@linux-foundation.org>
To: Russell King <linux@armlinux.org.uk>
To: Catalin Marinas <catalin.marinas@arm.com>
To: Mark Salter <msalter@redhat.com>
To: Tony Luck <tony.luck@intel.com>
To: David Howells <dhowells@redhat.com>
To: Yoshinori Sato <ysato@users.sourceforge.jp>
To: Guan Xuetao <gxt@mprc.pku.edu.cn>
To: Borislav Petkov <bp@alien8.de>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
To: Vineet Gupta <vgupta@synopsys.com>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-am33-list@redhat.com
Cc: linux-sh@vger.kernel.org
Cc: linux-edac@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
[pmladek@suse.com: updated commit message]
Signed-off-by: Petr Mladek <pmladek@suse.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>