Eric Lee / smarc-ti-linux-kernel

Download as
Browse Code ยป

Commit 2f4f9b92b2582f8c1706686cdbbe07d28530f8cc

Authored by Joonsoo Kim
Committed by Greg Kroah-Hartman
1 parent 522a8162a0

mm/CMA: fix boot regression due to physical address of high_memory 

commit 6b101e2a3ce4d2a0312087598bd1ab4a1db2ac40 upstream.

high_memory isn't direct mapped memory so retrieving it's physical address
isn't appropriate.  But, it would be useful to check physical address of
highmem boundary so it's justfiable to get physical address from it.  In
x86, there is a validation check if CONFIG_DEBUG_VIRTUAL and it triggers
following boot failure reported by Ingo.

  ...
  BUG: Int 6: CR2 00f06f53
  ...
  Call Trace:
    dump_stack+0x41/0x52
    early_idt_handler+0x6b/0x6b
    cma_declare_contiguous+0x33/0x212
    dma_contiguous_reserve_area+0x31/0x4e
    dma_contiguous_reserve+0x11d/0x125
    setup_arch+0x7b5/0xb63
    start_kernel+0xb8/0x3e6
    i386_start_kernel+0x79/0x7d

To fix boot regression, this patch implements workaround to avoid
validation check in x86 when retrieving physical address of high_memory.
__pa_nodebug() used by this patch is implemented only in x86 so there is
no choice but to use dirty #ifdef.

[akpm@linux-foundation.org: tweak comment]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reported-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Ingo Molnar <mingo@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Showing 1 changed file with 13 additions and 1 deletions Side-by-side Diff

... ... @@ -215,9 +215,21 @@
215 215 bool fixed, struct cma **res_cma)
216 216 {
217 217 phys_addr_t memblock_end = memblock_end_of_DRAM();
218   - phys_addr_t highmem_start = __pa(high_memory);
  218 + phys_addr_t highmem_start;
219 219 int ret = 0;
220 220  
  221 +#ifdef CONFIG_X86
  222 + /*
  223 + * high_memory isn't direct mapped memory so retrieving its physical
  224 + * address isn't appropriate. But it would be useful to check the
  225 + * physical address of the highmem boundary so it's justfiable to get
  226 + * the physical address from it. On x86 there is a validation check for
  227 + * this case, so the following workaround is needed to avoid it.
  228 + */
  229 + highmem_start = __pa_nodebug(high_memory);
  230 +#else
  231 + highmem_start = __pa(high_memory);
  232 +#endif
221 233 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
222 234 __func__, &size, &base, &limit, &alignment);
223 235