linux-stable.git/arch/mips/kernel, branch v3.2.92 Linux kernel stable tree MIPS: KGDB: Use kernel context for sleeping threads 2017-07-18T17:38:42+00:00 James Hogan james.hogan@imgtec.com 2017-03-30T15:06:02+00:00 c38cb25bdc9cdb7579dc9923ae204381fbaa9eaf commit 162b270c664dca2e0944308e92f9fcc887151a72 upstream. KGDB is a kernel debug stub and it can't be used to debug userland as it can only safely access kernel memory. On MIPS however KGDB has always got the register state of sleeping processes from the userland register context at the beginning of the kernel stack. This is meaningless for kernel threads (which never enter userland), and for user threads it prevents the user seeing what it is doing while in the kernel: (gdb) info threads Id Target Id Frame ... 3 Thread 2 (kthreadd) 0x0000000000000000 in ?? () 2 Thread 1 (init) 0x000000007705c4b4 in ?? () 1 Thread -2 (shadowCPU0) 0xffffffff8012524c in arch_kgdb_breakpoint () at arch/mips/kernel/kgdb.c:201 Get the register state instead from the (partial) kernel register context stored in the task's thread_struct for resume() to restore. All threads now correctly appear to be in context_switch(): (gdb) info threads Id Target Id Frame ... 3 Thread 2 (kthreadd) context_switch (rq=<optimized out>, cookie=..., next=<optimized out>, prev=0x0) at kernel/sched/core.c:2903 2 Thread 1 (init) context_switch (rq=<optimized out>, cookie=..., next=<optimized out>, prev=0x0) at kernel/sched/core.c:2903 1 Thread -2 (shadowCPU0) 0xffffffff8012524c in arch_kgdb_breakpoint () at arch/mips/kernel/kgdb.c:201 Call clobbered registers which aren't saved and exception registers (BadVAddr & Cause) which can't be easily determined without stack unwinding are reported as 0. The PC is taken from the return address, such that the state presented matches that found immediately after returning from resume(). Fixes: 8854700115ec ("[MIPS] kgdb: add arch support for the kernel's kgdb core") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/15829/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 162b270c664dca2e0944308e92f9fcc887151a72 upstream.

KGDB is a kernel debug stub and it can't be used to debug userland as it
can only safely access kernel memory.

On MIPS however KGDB has always got the register state of sleeping
processes from the userland register context at the beginning of the
kernel stack. This is meaningless for kernel threads (which never enter
userland), and for user threads it prevents the user seeing what it is
doing while in the kernel:

(gdb) info threads
  Id   Target Id         Frame
  ...
  3    Thread 2 (kthreadd) 0x0000000000000000 in ?? ()
  2    Thread 1 (init)   0x000000007705c4b4 in ?? ()
  1    Thread -2 (shadowCPU0) 0xffffffff8012524c in arch_kgdb_breakpoint () at arch/mips/kernel/kgdb.c:201

Get the register state instead from the (partial) kernel register
context stored in the task's thread_struct for resume() to restore. All
threads now correctly appear to be in context_switch():

(gdb) info threads
  Id   Target Id         Frame
  ...
  3    Thread 2 (kthreadd) context_switch (rq=<optimized out>, cookie=..., next=<optimized out>, prev=0x0) at kernel/sched/core.c:2903
  2    Thread 1 (init)   context_switch (rq=<optimized out>, cookie=..., next=<optimized out>, prev=0x0) at kernel/sched/core.c:2903
  1    Thread -2 (shadowCPU0) 0xffffffff8012524c in arch_kgdb_breakpoint () at arch/mips/kernel/kgdb.c:201

Call clobbered registers which aren't saved and exception registers
(BadVAddr & Cause) which can't be easily determined without stack
unwinding are reported as 0. The PC is taken from the return address,
such that the state presented matches that found immediately after
returning from resume().

Fixes: 8854700115ec ("[MIPS] kgdb: add arch support for the kernel's kgdb core")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15829/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
KEYS: 64-bit MIPS needs to use compat_sys_keyctl for 32-bit userspace 2016-11-20T01:01:29+00:00 David Howells dhowells@redhat.com 2016-07-27T10:43:37+00:00 51a8ffefe4ae40fdf8ab3b5ceb86f76231b94948 commit 20f06ed9f61a185c6dabd662c310bed6189470df upstream. MIPS64 needs to use compat_sys_keyctl for 32-bit userspace rather than calling sys_keyctl. The latter will work in a lot of cases, thereby hiding the issue. Reported-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: David Howells <dhowells@redhat.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: linux-security-module@vger.kernel.org Cc: keyrings@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13832/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 20f06ed9f61a185c6dabd662c310bed6189470df upstream.

MIPS64 needs to use compat_sys_keyctl for 32-bit userspace rather than
calling sys_keyctl.  The latter will work in a lot of cases, thereby hiding
the issue.

Reported-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: keyrings@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13832/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
MIPS: traps: Fix SIGFPE information leak from `do_ov' and `do_trap_or_bp' 2016-04-01T00:54:37+00:00 Maciej W. Rozycki macro@imgtec.com 2016-03-04T01:42:49+00:00 5476a24d66a7d275ed1e0a3113f26c1158684462 commit e723e3f7f9591b79e8c56b3d7c5a204a9c571b55 upstream. Avoid sending a partially initialised `siginfo_t' structure along SIGFPE signals issued from `do_ov' and `do_trap_or_bp', leading to information leaking from the kernel stack. Signed-off-by: Maciej W. Rozycki <macro@imgtec.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit e723e3f7f9591b79e8c56b3d7c5a204a9c571b55 upstream.

Avoid sending a partially initialised `siginfo_t' structure along SIGFPE
signals issued from `do_ov' and `do_trap_or_bp', leading to information
leaking from the kernel stack.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
MIPS: Fix restart of indirect syscalls 2016-01-22T21:40:08+00:00 Ed Swierk eswierk@skyportsystems.com 2015-01-13T05:10:30+00:00 08f865bba9c705aef95268a33393698e5385587e commit e967ef022e00bb7c2e5b1a42007abfdd52055050 upstream. When 32-bit MIPS userspace invokes a syscall indirectly via syscall(number, arg1, ..., arg7), the kernel looks up the actual syscall based on the given number, shifts the other arguments to the left, and jumps to the syscall. If the syscall is interrupted by a signal and indicates it needs to be restarted by the kernel (by returning ERESTARTNOINTR for example), the syscall must be called directly, since the number is no longer the first argument, and the other arguments are now staged for a direct call. Before shifting the arguments, store the syscall number in pt_regs->regs[2]. This gets copied temporarily into pt_regs->regs[0] after the syscall returns. If the syscall needs to be restarted, handle_signal()/do_signal() copies the number back to pt_regs->reg[2], which ends up in $v0 once control returns to userspace. Signed-off-by: Ed Swierk <eswierk@skyportsystems.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8929/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit e967ef022e00bb7c2e5b1a42007abfdd52055050 upstream.

When 32-bit MIPS userspace invokes a syscall indirectly via syscall(number,
arg1, ..., arg7), the kernel looks up the actual syscall based on the given
number, shifts the other arguments to the left, and jumps to the syscall.

If the syscall is interrupted by a signal and indicates it needs to be
restarted by the kernel (by returning ERESTARTNOINTR for example), the
syscall must be called directly, since the number is no longer the first
argument, and the other arguments are now staged for a direct call.

Before shifting the arguments, store the syscall number in pt_regs->regs[2].
This gets copied temporarily into pt_regs->regs[0] after the syscall returns.
If the syscall needs to be restarted, handle_signal()/do_signal() copies the
number back to pt_regs->reg[2], which ends up in $v0 once control returns to
userspace.

Signed-off-by: Ed Swierk <eswierk@skyportsystems.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8929/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
MIPS: Fix sched_getaffinity with MT FPAFF enabled 2015-10-13T02:46:01+00:00 Felix Fietkau nbd@openwrt.org 2015-07-18T22:38:41+00:00 226302bdd94de8fd2a772f8c233b5e638ff56959 commit 1d62d737555e1378eb62a8bba26644f7d97139d2 upstream. p->thread.user_cpus_allowed is zero-initialized and is only filled on the first sched_setaffinity call. To avoid adding overhead in the task initialization codepath, simply OR the returned mask in sched_getaffinity with p->cpus_allowed. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/10740/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> [bwh: Backported to 3.2: also convert from obsolete cpumask API] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 1d62d737555e1378eb62a8bba26644f7d97139d2 upstream.

p->thread.user_cpus_allowed is zero-initialized and is only filled on
the first sched_setaffinity call.

To avoid adding overhead in the task initialization codepath, simply OR
the returned mask in sched_getaffinity with p->cpus_allowed.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10740/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
[bwh: Backported to 3.2: also convert from obsolete cpumask API]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
MIPS: Fix enabling of DEBUG_STACKOVERFLOW 2015-08-06T23:32:15+00:00 James Hogan james.hogan@imgtec.com 2015-06-04T12:25:27+00:00 b9cc09945dcaebcafd8d20bf0445630820a0b40d commit 5f35b9cd553fd64415b563497d05a563c988dbd6 upstream. Commit 334c86c494b9 ("MIPS: IRQ: Add stackoverflow detection") added kernel stack overflow detection, however it only enabled it conditional upon the preprocessor definition DEBUG_STACKOVERFLOW, which is never actually defined. The Kconfig option is called DEBUG_STACKOVERFLOW, which manifests to the preprocessor as CONFIG_DEBUG_STACKOVERFLOW, so switch it to using that definition instead. Fixes: 334c86c494b9 ("MIPS: IRQ: Add stackoverflow detection") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Adam Jiang <jiang.adam@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/10531/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 5f35b9cd553fd64415b563497d05a563c988dbd6 upstream.

Commit 334c86c494b9 ("MIPS: IRQ: Add stackoverflow detection") added
kernel stack overflow detection, however it only enabled it conditional
upon the preprocessor definition DEBUG_STACKOVERFLOW, which is never
actually defined. The Kconfig option is called DEBUG_STACKOVERFLOW,
which manifests to the preprocessor as CONFIG_DEBUG_STACKOVERFLOW, so
switch it to using that definition instead.

Fixes: 334c86c494b9 ("MIPS: IRQ: Add stackoverflow detection")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Adam Jiang <jiang.adam@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/10531/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
MIPS: Fix kernel lockup or crash after CPU offline/online 2015-03-06T00:39:18+00:00 Hemmo Nieminen hemmo.nieminen@iki.fi 2015-01-15T21:01:59+00:00 7829c20e43e9f915231e8b7c97aaa1acc9133126 commit c7754e75100ed5e3068ac5085747f2bfc386c8d6 upstream. As printk() invocation can cause e.g. a TLB miss, printk() cannot be called before the exception handlers have been properly initialized. This can happen e.g. when netconsole has been loaded as a kernel module and the TLB table has been cleared when a CPU was offline. Call cpu_report() in start_secondary() only after the exception handlers have been initialized to fix this. Without the patch the kernel will randomly either lockup or crash after a CPU is onlined and the console driver is a module. Signed-off-by: Hemmo Nieminen <hemmo.nieminen@iki.fi> Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi> Cc: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/8953/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit c7754e75100ed5e3068ac5085747f2bfc386c8d6 upstream.

As printk() invocation can cause e.g. a TLB miss, printk() cannot be
called before the exception handlers have been properly initialized.
This can happen e.g. when netconsole has been loaded as a kernel module
and the TLB table has been cleared when a CPU was offline.

Call cpu_report() in start_secondary() only after the exception handlers
have been initialized to fix this.

Without the patch the kernel will randomly either lockup or crash
after a CPU is onlined and the console driver is a module.

Signed-off-by: Hemmo Nieminen <hemmo.nieminen@iki.fi>
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8953/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
MIPS: IRQ: Fix disable_irq on CPU IRQs 2015-03-06T00:39:17+00:00 Felix Fietkau nbd@openwrt.org 2015-01-15T18:05:28+00:00 c5780dc7c2c76e76cfc20d4b5a6bb2a4540fa92d commit a3e6c1eff54878506b2dddcc202df9cc8180facb upstream. If the irq_chip does not define .irq_disable, any call to disable_irq will defer disabling the IRQ until it fires while marked as disabled. This assumes that the handler function checks for this condition, which handle_percpu_irq does not. In this case, calling disable_irq leads to an IRQ storm, if the interrupt fires while disabled. This optimization is only useful when disabling the IRQ is slow, which is not true for the MIPS CPU IRQ. Disable this optimization by implementing .irq_disable and .irq_enable Signed-off-by: Felix Fietkau <nbd@openwrt.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8949/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit a3e6c1eff54878506b2dddcc202df9cc8180facb upstream.

If the irq_chip does not define .irq_disable, any call to disable_irq
will defer disabling the IRQ until it fires while marked as disabled.
This assumes that the handler function checks for this condition, which
handle_percpu_irq does not. In this case, calling disable_irq leads to
an IRQ storm, if the interrupt fires while disabled.

This optimization is only useful when disabling the IRQ is slow, which
is not true for the MIPS CPU IRQ.

Disable this optimization by implementing .irq_disable and .irq_enable

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8949/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
MIPS: mcount: Adjust stack pointer for static trace in MIPS32 2014-11-05T20:27:46+00:00 Markos Chandras markos.chandras@imgtec.com 2014-09-16T14:55:12+00:00 bbc3708af2adfb001b3df0e9e7479d10082772c2 commit 8a574cfa2652545eb95595d38ac2a0bb501af0ae upstream. Every mcount() call in the MIPS 32-bit kernel is done as follows: [...] move at, ra jal _mcount addiu sp, sp, -8 [...] but upon returning from the mcount() function, the stack pointer is not adjusted properly. This is explained in details in 58b69401c797 (MIPS: Function tracer: Fix broken function tracing). Commit ad8c396936e3 ("MIPS: Unbreak function tracer for 64-bit kernel.) fixed the stack manipulation for 64-bit but it didn't fix it completely for MIPS32. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7792/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 8a574cfa2652545eb95595d38ac2a0bb501af0ae upstream.

Every mcount() call in the MIPS 32-bit kernel is done as follows:

[...]
move at, ra
jal _mcount
addiu sp, sp, -8
[...]

but upon returning from the mcount() function, the stack pointer
is not adjusted properly. This is explained in details in 58b69401c797
(MIPS: Function tracer: Fix broken function tracing).

Commit ad8c396936e3 ("MIPS: Unbreak function tracer for 64-bit kernel.)
fixed the stack manipulation for 64-bit but it didn't fix it completely
for MIPS32.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7792/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
MIPS: perf: Fix build error caused by unused counters_per_cpu_to_total() 2014-09-13T22:41:48+00:00 Florian Fainelli florian@openwrt.org 2012-07-19T07:13:52+00:00 588ca81b421339a30b3328e8f7e8f00fd0c9afdf commit 6c37c9580409af7dc664bb6af0a85d540d63aeea upstream. cc1: warnings being treated as errors arch/mips/kernel/perf_event_mipsxx.c:166: error: 'counters_per_cpu_to_total' defined but not used make[2]: *** [arch/mips/kernel/perf_event_mipsxx.o] Error 1 make[2]: *** Waiting for unfinished jobs.... It was first introduced by 82091564cfd7ab8def42777a9c662dbf655c5d25 [MIPS: perf: Add support for 64-bit perf counters.] in 3.2. Signed-off-by: Florian Fainelli <florian@openwrt.org> Cc: linux-mips@linux-mips.org Cc: david.daney@cavium.com Patchwork: https://patchwork.linux-mips.org/patch/3357/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 6c37c9580409af7dc664bb6af0a85d540d63aeea upstream.

cc1: warnings being treated as errors
arch/mips/kernel/perf_event_mipsxx.c:166: error: 'counters_per_cpu_to_total' defined but not used
make[2]: *** [arch/mips/kernel/perf_event_mipsxx.o] Error 1
make[2]: *** Waiting for unfinished jobs....

It was first introduced by 82091564cfd7ab8def42777a9c662dbf655c5d25 [MIPS:
perf: Add support for 64-bit perf counters.] in 3.2.

Signed-off-by: Florian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: david.daney@cavium.com
Patchwork: https://patchwork.linux-mips.org/patch/3357/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>