2020-12-03 12:40:08

by Alexander Sverdlin

Subject: [PATCH 1/2] MIPS: Don't round up kernel sections size for memblock_add()

From: Alexander Sverdlin <[email protected]>

Linux doesn't own the memory immediately after the kernel image. On Octeon
bootloader places a shared structure right close after the kernel _end,
refer to "struct cvmx_bootinfo *octeon_bootinfo" in cavium-octeon/setup.c.

If check_kernel_sections_mem() rounds the PFNs up, first memblock_alloc()
inside early_init_dt_alloc_memory_arch() <= device_tree_init() returns
memory block overlapping with the above octeon_bootinfo structure, which
is being overwritten afterwards.

Fixes: a94e4f24ec83 ("MIPS: init: Drop boot_mem_map")
Signed-off-by: Alexander Sverdlin <[email protected]>
---
arch/mips/kernel/setup.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index ca579de..9d11f68 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -498,8 +498,8 @@ static void __init request_crashkernel(struct resource *res)

static void __init check_kernel_sections_mem(void)
{
- phys_addr_t start = PFN_PHYS(PFN_DOWN(__pa_symbol(&_text)));
- phys_addr_t size = PFN_PHYS(PFN_UP(__pa_symbol(&_end))) - start;
+ phys_addr_t start = __pa_symbol(&_text);
+ phys_addr_t size = __pa_symbol(&_end) - start;

if (!memblock_is_region_memory(start, size)) {
pr_info("Kernel sections are not in the memory maps\n");
--
2.10.2

2020-12-03 12:42:24

by Alexander Sverdlin

Subject: [PATCH 2/2] MIPS: OCTEON: Don't add kernel sections into memblock allocator

From: Alexander Sverdlin <[email protected]>

Because check_kernel_sections_mem() does exactly this for all platforms.

Signed-off-by: Alexander Sverdlin <[email protected]>
---
arch/mips/cavium-octeon/setup.c | 9 ---------
1 file changed, 9 deletions(-)

diff --git a/arch/mips/cavium-octeon/setup.c b/arch/mips/cavium-octeon/setup.c
index d051a8a..34cef11 100644
--- a/arch/mips/cavium-octeon/setup.c
+++ b/arch/mips/cavium-octeon/setup.c
@@ -1013,8 +1013,6 @@ void __init plat_mem_setup(void)
uint64_t crashk_end;
#ifndef CONFIG_CRASH_DUMP
int64_t memory;
- uint64_t kernel_start;
- uint64_t kernel_size;
#endif

total = 0;
@@ -1152,13 +1150,6 @@ void __init plat_mem_setup(void)
}
}
cvmx_bootmem_unlock();
- /* Add the memory region for the kernel. */
- kernel_start = (unsigned long) _text;
- kernel_size = _end - _text;
-
- /* Adjust for physical offset. */
- kernel_start &= ~0xffffffff80000000ULL;
- memblock_add(kernel_start, kernel_size);
#endif /* CONFIG_CRASH_DUMP */

#ifdef CONFIG_CAVIUM_RESERVE32
--
2.10.2

2020-12-04 12:13:07

by Thomas Bogendoerfer

Subject: Re: [PATCH 2/2] MIPS: OCTEON: Don't add kernel sections into memblock allocator

On Thu, Dec 03, 2020 at 01:36:49PM +0100, Alexander A Sverdlin wrote:
> From: Alexander Sverdlin <[email protected]>
>
> Because check_kernel_sections_mem() does exactly this for all platforms.
>
> Signed-off-by: Alexander Sverdlin <[email protected]>
> ---
> arch/mips/cavium-octeon/setup.c | 9 ---------
> 1 file changed, 9 deletions(-)

applied to mips-next.

Thomas.

--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]

2020-12-04 12:14:27

by Thomas Bogendoerfer

Subject: Re: [PATCH 1/2] MIPS: Don't round up kernel sections size for memblock_add()

On Thu, Dec 03, 2020 at 01:36:48PM +0100, Alexander A Sverdlin wrote:
> From: Alexander Sverdlin <[email protected]>
>
> Linux doesn't own the memory immediately after the kernel image. On Octeon
> bootloader places a shared structure right close after the kernel _end,
> refer to "struct cvmx_bootinfo *octeon_bootinfo" in cavium-octeon/setup.c.
>
> If check_kernel_sections_mem() rounds the PFNs up, first memblock_alloc()
> inside early_init_dt_alloc_memory_arch() <= device_tree_init() returns
> memory block overlapping with the above octeon_bootinfo structure, which
> is being overwritten afterwards.
>
> Fixes: a94e4f24ec83 ("MIPS: init: Drop boot_mem_map")
> Signed-off-by: Alexander Sverdlin <[email protected]>
> ---
> arch/mips/kernel/setup.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

applied to mips-next.

Thomas.

--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]