[PATCH 4.9 009/104] MIPS: Ensure bss section ends on a long-aligned address

[PATCH 4.9 009/104] MIPS: Ensure bss section ends on a long-aligned address

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paul Burton <paul.burton@imgtec.com>


[ Upstream commit 3f00f4d8f083bc61005d0a1ef592b149f5c88bbd ]

When clearing the .bss section in kernel_entry we do so using LONG_S
instructions, and branch whilst the current write address doesn't equal
the end of the .bss section minus the size of a long integer. The .bss
section always begins at a long-aligned address and we always increment
the write pointer by the size of a long integer - we therefore rely upon
the .bss section ending at a long-aligned address. If this is not the
case then the long-aligned write address can never be equal to the
non-long-aligned end address & we will continue to increment past the
end of the .bss section, attempting to zero the rest of memory.

Despite this requirement that .bss end at a long-aligned address we pass
0 as the end alignment requirement to the BSS_SECTION macro and thus
don't guarantee any particular alignment, allowing us to hit the error
condition described above.

Fix this by instead passing 8 bytes as the end alignment argument to
the BSS_SECTION macro, ensuring that the end of the .bss section is
always at least long-aligned.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14526/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/mips/kernel/vmlinux.lds.S |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/arch/mips/kernel/vmlinux.lds.S
@@ -182,7 +182,7 @@ SECTIONS
 	 * Force .bss to 64K alignment so that .bss..swapper_pg_dir
 	 * gets that alignment.	 .sbss should be empty, so there will be
 	 * no holes after __init_end. */
-	BSS_SECTION(0, 0x10000, 0)
+	BSS_SECTION(0, 0x10000, 8)
 
 	_end = . ;
 

[PATCH 4.9 010/104] MIPS: fix mem=X@Y commandline processing

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marcin Nowakowski <marcin.nowakowski@imgtec.com>


[ Upstream commit 73fbc1eba7ffa3bf0ad12486232a8a1edb4e4411 ]

When a memory offset is specified through the commandline, add the
memory in range PHYS_OFFSET:Y as reserved memory area.
Otherwise the bootmem allocator is initialised with low page equal to
min_low_pfn = PHYS_OFFSET, and in free_all_bootmem will process pages
starting from min_low_pfn instead of PFN(Y).

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14613/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/mips/kernel/setup.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -589,6 +589,10 @@ static int __init early_parse_mem(char *
 		start = memparse(p + 1, &p);
 
 	add_memory_region(start, size, BOOT_MEM_RAM);
+
+	if (start && start > PHYS_OFFSET)
+		add_memory_region(PHYS_OFFSET, start - PHYS_OFFSET,
+				BOOT_MEM_RESERVED);
 	return 0;
 }
 early_param("mem", early_parse_mem);

Re: [PATCH 4.9 010/104] MIPS: fix mem=X@Y commandline processing

[Mathieu Malaterre]

Hi Greg,

Please do not apply to stable.

See: https://patchwork.linux-mips.org/patch/17235/

Thanks

On Fri, Oct 6, 2017 at 10:50 AM, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> 4.9-stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> From: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
>
>
> [ Upstream commit 73fbc1eba7ffa3bf0ad12486232a8a1edb4e4411 ]
>
> When a memory offset is specified through the commandline, add the
> memory in range PHYS_OFFSET:Y as reserved memory area.
> Otherwise the bootmem allocator is initialised with low page equal to
> min_low_pfn = PHYS_OFFSET, and in free_all_bootmem will process pages
> starting from min_low_pfn instead of PFN(Y).
>
> Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
> Cc: linux-mips@linux-mips.org
> Patchwork: https://patchwork.linux-mips.org/patch/14613/
> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  arch/mips/kernel/setup.c |    4 ++++
>  1 file changed, 4 insertions(+)
>
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -589,6 +589,10 @@ static int __init early_parse_mem(char *
>                 start = memparse(p + 1, &p);
>
>         add_memory_region(start, size, BOOT_MEM_RAM);
> +
> +       if (start && start > PHYS_OFFSET)
> +               add_memory_region(PHYS_OFFSET, start - PHYS_OFFSET,
> +                               BOOT_MEM_RESERVED);
>         return 0;
>  }
>  early_param("mem", early_parse_mem);
>
>
>

Re: [PATCH 4.9 010/104] MIPS: fix mem=X@Y commandline processing

[Greg Kroah-Hartman]

On Fri, Oct 06, 2017 at 11:10:11AM +0200, Mathieu Malaterre wrote:
> Hi Greg,
> 
> Please do not apply to stable.
> 
> See: https://patchwork.linux-mips.org/patch/17235/

Ah, so will you send this and that one for 4.9 when it hits Linus's
tree?

I'll go drop this one now, thanks.

greg k-h

Re: [PATCH 4.9 010/104] MIPS: fix mem=X@Y commandline processing

[Mathieu Malaterre]

On Fri, Oct 6, 2017 at 11:18 AM, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> On Fri, Oct 06, 2017 at 11:10:11AM +0200, Mathieu Malaterre wrote:
>> Hi Greg,
>>
>> Please do not apply to stable.
>>
>> See: https://patchwork.linux-mips.org/patch/17235/
>
> Ah, so will you send this and that one for 4.9 when it hits Linus's
> tree?
>
> I'll go drop this one now, thanks.

Sorry I meant to say do not apply to '4.9 stable branch'. For the
other stable branches, I suspect this is just a matter of days before
Ralf sends the updated fix.

-M

[PATCH 4.9 011/104] MIPS: kexec: Do not reserve invalid crashkernel memory on boot

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marcin Nowakowski <marcin.nowakowski@imgtec.com>


[ Upstream commit a8f108d70c74d83574c157648383eb2e4285a190 ]

Do not reserve memory for the crashkernel if the commandline argument
points to a wrong location. This can happen if the location is specified
wrong or if the same commandline is reused when starting the crashkernel
- in the latter case the reserved memory would point to the location
from which the crashkernel is executing.

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14612/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/mips/kernel/setup.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -668,6 +668,11 @@ static void __init mips_parse_crashkerne
 	if (ret != 0 || crash_size <= 0)
 		return;
 
+	if (!memory_region_available(crash_base, crash_size)) {
+		pr_warn("Invalid memory region reserved for crash kernel\n");
+		return;
+	}
+
 	crashk_res.start = crash_base;
 	crashk_res.end	 = crash_base + crash_size - 1;
 }

[PATCH 4.9 012/104] MIPS: ralink: Fix a typo in the pinmux setup.

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: John Crispin <john@phrozen.org>


[ Upstream commit 58181a117d353427127a2e7afc7cf1ab44759828 ]

There is a typo inside the pinmux setup code. The function is really
called utif and not util. This was recently discovered when people were
trying to make the UTIF interface work.

Signed-off-by: John Crispin <john@phrozen.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14899/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/mips/ralink/mt7620.c |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

--- a/arch/mips/ralink/mt7620.c
+++ b/arch/mips/ralink/mt7620.c
@@ -176,7 +176,7 @@ static struct rt2880_pmx_func spi_cs1_gr
 
 static struct rt2880_pmx_func spis_grp_mt7628[] = {
 	FUNC("pwm_uart2", 3, 14, 4),
-	FUNC("util", 2, 14, 4),
+	FUNC("utif", 2, 14, 4),
 	FUNC("gpio", 1, 14, 4),
 	FUNC("spis", 0, 14, 4),
 };
@@ -190,28 +190,28 @@ static struct rt2880_pmx_func gpio_grp_m
 
 static struct rt2880_pmx_func p4led_kn_grp_mt7628[] = {
 	FUNC("jtag", 3, 30, 1),
-	FUNC("util", 2, 30, 1),
+	FUNC("utif", 2, 30, 1),
 	FUNC("gpio", 1, 30, 1),
 	FUNC("p4led_kn", 0, 30, 1),
 };
 
 static struct rt2880_pmx_func p3led_kn_grp_mt7628[] = {
 	FUNC("jtag", 3, 31, 1),
-	FUNC("util", 2, 31, 1),
+	FUNC("utif", 2, 31, 1),
 	FUNC("gpio", 1, 31, 1),
 	FUNC("p3led_kn", 0, 31, 1),
 };
 
 static struct rt2880_pmx_func p2led_kn_grp_mt7628[] = {
 	FUNC("jtag", 3, 32, 1),
-	FUNC("util", 2, 32, 1),
+	FUNC("utif", 2, 32, 1),
 	FUNC("gpio", 1, 32, 1),
 	FUNC("p2led_kn", 0, 32, 1),
 };
 
 static struct rt2880_pmx_func p1led_kn_grp_mt7628[] = {
 	FUNC("jtag", 3, 33, 1),
-	FUNC("util", 2, 33, 1),
+	FUNC("utif", 2, 33, 1),
 	FUNC("gpio", 1, 33, 1),
 	FUNC("p1led_kn", 0, 33, 1),
 };
@@ -232,28 +232,28 @@ static struct rt2880_pmx_func wled_kn_gr
 
 static struct rt2880_pmx_func p4led_an_grp_mt7628[] = {
 	FUNC("jtag", 3, 39, 1),
-	FUNC("util", 2, 39, 1),
+	FUNC("utif", 2, 39, 1),
 	FUNC("gpio", 1, 39, 1),
 	FUNC("p4led_an", 0, 39, 1),
 };
 
 static struct rt2880_pmx_func p3led_an_grp_mt7628[] = {
 	FUNC("jtag", 3, 40, 1),
-	FUNC("util", 2, 40, 1),
+	FUNC("utif", 2, 40, 1),
 	FUNC("gpio", 1, 40, 1),
 	FUNC("p3led_an", 0, 40, 1),
 };
 
 static struct rt2880_pmx_func p2led_an_grp_mt7628[] = {
 	FUNC("jtag", 3, 41, 1),
-	FUNC("util", 2, 41, 1),
+	FUNC("utif", 2, 41, 1),
 	FUNC("gpio", 1, 41, 1),
 	FUNC("p2led_an", 0, 41, 1),
 };
 
 static struct rt2880_pmx_func p1led_an_grp_mt7628[] = {
 	FUNC("jtag", 3, 42, 1),
-	FUNC("util", 2, 42, 1),
+	FUNC("utif", 2, 42, 1),
 	FUNC("gpio", 1, 42, 1),
 	FUNC("p1led_an", 0, 42, 1),
 };

[PATCH 4.9 013/104] MIPS: ralink: Fix incorrect assignment on ralink_soc

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Colin Ian King <colin.king@canonical.com>


[ Upstream commit 08d90c81b714482dceb5323d14f6617bcf55ee61 ]

ralink_soc sould be assigned to RT3883_SOC, replace incorrect
comparision with assignment.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Fixes: 418d29c87061 ("MIPS: ralink: Unify SoC id handling")
Cc: John Crispin <john@phrozen.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14903/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/mips/ralink/rt3883.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/mips/ralink/rt3883.c
+++ b/arch/mips/ralink/rt3883.c
@@ -145,5 +145,5 @@ void prom_soc_init(struct ralink_soc_inf
 
 	rt2880_pinmux_data = rt3883_pinmux_data;
 
-	ralink_soc == RT3883_SOC;
+	ralink_soc = RT3883_SOC;
 }

[PATCH 4.9 055/104] MIPS: Lantiq: Fix another request_mem_region() return code check

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@arndb.de>


[ Upstream commit 98ea51cb0c8ce009d9da1fd7b48f0ff1d7a9bbb0 ]

Hauke already fixed a couple of them, but one instance remains
that checks for a negative integer when it should check
for a NULL pointer:

arch/mips/lantiq/xway/sysctrl.c: In function 'ltq_soc_init':
arch/mips/lantiq/xway/sysctrl.c:473:19: error: ordered comparison of pointer with integer zero [-Werror=extra]

Fixes: 6e807852676a ("MIPS: Lantiq: Fix check for return value of request_mem_region()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: John Crispin <john@phrozen.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/15043/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/mips/lantiq/xway/sysctrl.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/mips/lantiq/xway/sysctrl.c
+++ b/arch/mips/lantiq/xway/sysctrl.c
@@ -469,8 +469,8 @@ void __init ltq_soc_init(void)
 			panic("Failed to load xbar nodes from devicetree");
 		if (of_address_to_resource(np_xbar, 0, &res_xbar))
 			panic("Failed to get xbar resources");
-		if (request_mem_region(res_xbar.start, resource_size(&res_xbar),
-			res_xbar.name) < 0)
+		if (!request_mem_region(res_xbar.start, resource_size(&res_xbar),
+			res_xbar.name))
 			panic("Failed to get xbar resources");
 
 		ltq_xbar_membase = ioremap_nocache(res_xbar.start,

[PATCH 4.9 056/104] mips: ath79: clock:- Unmap region obtained by of_iomap

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arvind Yadav <arvind.yadav.cs@gmail.com>


[ Upstream commit b3d91db3f71d5f70ea60d900425a3f96aeb3d065 ]

Free memory mapping, if ath79_clocks_init_dt_ng is not successful.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Fixes: 3bdf1071ba7d ("MIPS: ath79: update devicetree clock support for AR9132")
Cc: antonynpavlov@gmail.com
Cc: albeu@free.fr
Cc: hackpascal@gmail.com
Cc: sboyd@codeaurora.org
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14915/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/mips/ath79/clock.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/arch/mips/ath79/clock.c
+++ b/arch/mips/ath79/clock.c
@@ -508,16 +508,19 @@ static void __init ath79_clocks_init_dt_
 		ar9330_clk_init(ref_clk, pll_base);
 	else {
 		pr_err("%s: could not find any appropriate clk_init()\n", dnfn);
-		goto err_clk;
+		goto err_iounmap;
 	}
 
 	if (of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data)) {
 		pr_err("%s: could not register clk provider\n", dnfn);
-		goto err_clk;
+		goto err_iounmap;
 	}
 
 	return;
 
+err_iounmap:
+	iounmap(pll_base);
+
 err_clk:
 	clk_put(ref_clk);
 

[PATCH 4.9 074/104] MIPS: IRQ Stack: Unwind IRQ stack onto task stack

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matt Redfearn <matt.redfearn@imgtec.com>


[ Upstream commit db8466c581cca1a08b505f1319c3ecd246f16fa8 ]

When the separate IRQ stack was introduced, stack unwinding only
proceeded as far as the top of the IRQ stack, leading to kernel
backtraces being less useful, lacking the trace of what was interrupted.

Fix this by providing a means for the kernel to unwind the IRQ stack
onto the interrupted task stack. The processor state is saved to the
kernel task stack on interrupt. The IRQ_STACK_START macro reserves an
unsigned long at the top of the IRQ stack where the interrupted task
stack pointer can be saved. After the active stack is switched to the
IRQ stack, save the interrupted tasks stack pointer to the reserved
location.

Fix the stack unwinding code to look for the frame being the top of the
IRQ stack and if so get the next frame from the saved location. The
existing test does not work with the separate stack since the ra is no
longer pointed at ret_from_{irq,exception}.

The test to stop unwinding the stack 32 bytes from the top of a stack
must be modified to allow unwinding to continue up to the location of
the saved task stack pointer when on the IRQ stack. The low / high marks
of the stack are set depending on whether the sp is on an irq stack or
not.

Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: Masanari Iida <standby24x7@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason A. Donenfeld <jason@zx2c4.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/15788/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/mips/include/asm/irq.h    |   15 ++++++++++
 arch/mips/kernel/asm-offsets.c |    1 
 arch/mips/kernel/genex.S       |    8 ++++-
 arch/mips/kernel/process.c     |   56 +++++++++++++++++++++++++++--------------
 4 files changed, 60 insertions(+), 20 deletions(-)

--- a/arch/mips/include/asm/irq.h
+++ b/arch/mips/include/asm/irq.h
@@ -18,9 +18,24 @@
 #include <irq.h>
 
 #define IRQ_STACK_SIZE			THREAD_SIZE
+#define IRQ_STACK_START			(IRQ_STACK_SIZE - sizeof(unsigned long))
 
 extern void *irq_stack[NR_CPUS];
 
+/*
+ * The highest address on the IRQ stack contains a dummy frame put down in
+ * genex.S (handle_int & except_vec_vi_handler) which is structured as follows:
+ *
+ *   top ------------
+ *       | task sp  | <- irq_stack[cpu] + IRQ_STACK_START
+ *       ------------
+ *       |          | <- First frame of IRQ context
+ *       ------------
+ *
+ * task sp holds a copy of the task stack pointer where the struct pt_regs
+ * from exception entry can be found.
+ */
+
 static inline bool on_irq_stack(int cpu, unsigned long sp)
 {
 	unsigned long low = (unsigned long)irq_stack[cpu];
--- a/arch/mips/kernel/asm-offsets.c
+++ b/arch/mips/kernel/asm-offsets.c
@@ -103,6 +103,7 @@ void output_thread_info_defines(void)
 	DEFINE(_THREAD_SIZE, THREAD_SIZE);
 	DEFINE(_THREAD_MASK, THREAD_MASK);
 	DEFINE(_IRQ_STACK_SIZE, IRQ_STACK_SIZE);
+	DEFINE(_IRQ_STACK_START, IRQ_STACK_START);
 	BLANK();
 }
 
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -215,9 +215,11 @@ NESTED(handle_int, PT_SIZE, sp)
 	beq	t0, t1, 2f
 
 	/* Switch to IRQ stack */
-	li	t1, _IRQ_STACK_SIZE
+	li	t1, _IRQ_STACK_START
 	PTR_ADD sp, t0, t1
 
+	/* Save task's sp on IRQ stack so that unwinding can follow it */
+	LONG_S	s1, 0(sp)
 2:
 	jal	plat_irq_dispatch
 
@@ -325,9 +327,11 @@ NESTED(except_vec_vi_handler, 0, sp)
 	beq	t0, t1, 2f
 
 	/* Switch to IRQ stack */
-	li	t1, _IRQ_STACK_SIZE
+	li	t1, _IRQ_STACK_START
 	PTR_ADD sp, t0, t1
 
+	/* Save task's sp on IRQ stack so that unwinding can follow it */
+	LONG_S	s1, 0(sp)
 2:
 	jalr	v0
 
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -487,31 +487,52 @@ unsigned long notrace unwind_stack_by_ad
 					      unsigned long pc,
 					      unsigned long *ra)
 {
+	unsigned long low, high, irq_stack_high;
 	struct mips_frame_info info;
 	unsigned long size, ofs;
+	struct pt_regs *regs;
 	int leaf;
-	extern void ret_from_irq(void);
-	extern void ret_from_exception(void);
 
 	if (!stack_page)
 		return 0;
 
 	/*
-	 * If we reached the bottom of interrupt context,
-	 * return saved pc in pt_regs.
+	 * IRQ stacks start at IRQ_STACK_START
+	 * task stacks at THREAD_SIZE - 32
 	 */
-	if (pc == (unsigned long)ret_from_irq ||
-	    pc == (unsigned long)ret_from_exception) {
-		struct pt_regs *regs;
-		if (*sp >= stack_page &&
-		    *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
-			regs = (struct pt_regs *)*sp;
-			pc = regs->cp0_epc;
-			if (!user_mode(regs) && __kernel_text_address(pc)) {
-				*sp = regs->regs[29];
-				*ra = regs->regs[31];
-				return pc;
-			}
+	low = stack_page;
+	if (!preemptible() && on_irq_stack(raw_smp_processor_id(), *sp)) {
+		high = stack_page + IRQ_STACK_START;
+		irq_stack_high = high;
+	} else {
+		high = stack_page + THREAD_SIZE - 32;
+		irq_stack_high = 0;
+	}
+
+	/*
+	 * If we reached the top of the interrupt stack, start unwinding
+	 * the interrupted task stack.
+	 */
+	if (unlikely(*sp == irq_stack_high)) {
+		unsigned long task_sp = *(unsigned long *)*sp;
+
+		/*
+		 * Check that the pointer saved in the IRQ stack head points to
+		 * something within the stack of the current task
+		 */
+		if (!object_is_on_stack((void *)task_sp))
+			return 0;
+
+		/*
+		 * Follow pointer to tasks kernel stack frame where interrupted
+		 * state was saved.
+		 */
+		regs = (struct pt_regs *)task_sp;
+		pc = regs->cp0_epc;
+		if (!user_mode(regs) && __kernel_text_address(pc)) {
+			*sp = regs->regs[29];
+			*ra = regs->regs[31];
+			return pc;
 		}
 		return 0;
 	}
@@ -532,8 +553,7 @@ unsigned long notrace unwind_stack_by_ad
 	if (leaf < 0)
 		return 0;
 
-	if (*sp < stack_page ||
-	    *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
+	if (*sp < low || *sp + info.frame_size > high)
 		return 0;
 
 	if (leaf)

[PATCH 4.9 077/104] MIPS: smp-cps: Fix retrieval of VPE mask on big endian CPUs

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matt Redfearn <matt.redfearn@imgtec.com>


[ Upstream commit fb2155e3c30dc2043b52020e26965067a3e7779c ]

The vpe_mask member of struct core_boot_config is of type atomic_t,
which is a 32bit type. In cps-vec.S this member was being retrieved by a
PTR_L macro, which on 64bit systems is a 64bit load. On little endian
systems this is OK, since the double word that is retrieved will have
the required less significant word in the correct position. However, on
big endian systems the less significant word of the load is retrieved
from address+4, and the more significant from address+0. The destination
register therefore ends up with the required word in the more
significant word
e.g. when starting the second VP of a big endian 64bit system, the load

PTR_L    ta2, COREBOOTCFG_VPEMASK(a0)

ends up setting register ta2 to 0x0000000300000000

When this value is written to the CPC it is ignored, since it is
invalid to write anything larger than 4 bits. This results in any VP
other than VP0 in a core failing to start in 64bit big endian systems.

Change the load to a 32bit load word instruction to fix the bug.

Fixes: f12401d7219f ("MIPS: smp-cps: Pull boot config retrieval out of mips_cps_boot_vpes")
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/15787/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/mips/kernel/cps-vec.S |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/mips/kernel/cps-vec.S
+++ b/arch/mips/kernel/cps-vec.S
@@ -361,7 +361,7 @@ LEAF(mips_cps_get_bootcfg)
 	END(mips_cps_get_bootcfg)
 
 LEAF(mips_cps_boot_vpes)
-	PTR_L	ta2, COREBOOTCFG_VPEMASK(a0)
+	lw	ta2, COREBOOTCFG_VPEMASK(a0)
 	PTR_L	ta3, COREBOOTCFG_VPECONFIG(a0)
 
 #if defined(CONFIG_CPU_MIPSR6)