Revision a927bd6ba952d13c52b8b385030943032f659a3e authored by Dan Williams on 22 November 2020, 06:17:05 UTC, committed by Linus Torvalds on 22 November 2020, 18:48:22 UTC
The core-mm has a default __weak implementation of phys_to_target_node() to mirror the weak definition of memory_add_physaddr_to_nid(). That symbol is exported for modules. However, while the export in mm/memory_hotplug.c exported the symbol in the configuration cases of: CONFIG_NUMA_KEEP_MEMINFO=y CONFIG_MEMORY_HOTPLUG=y ...and: CONFIG_NUMA_KEEP_MEMINFO=n CONFIG_MEMORY_HOTPLUG=y ...it failed to export the symbol in the case of: CONFIG_NUMA_KEEP_MEMINFO=y CONFIG_MEMORY_HOTPLUG=n Not only is that broken, but Christoph points out that the kernel should not be exporting any __weak symbol, which means that memory_add_physaddr_to_nid() example that phys_to_target_node() copied is broken too. Rework the definition of phys_to_target_node() and memory_add_physaddr_to_nid() to not require weak symbols. Move to the common arch override design-pattern of an asm header defining a symbol to replace the default implementation. The only common header that all memory_add_physaddr_to_nid() producing architectures implement is asm/sparsemem.h. In fact, powerpc already defines its memory_add_physaddr_to_nid() helper in sparsemem.h. Double-down on that observation and define phys_to_target_node() where necessary in asm/sparsemem.h. An alternate consideration that was discarded was to put this override in asm/numa.h, but that entangles with the definition of MAX_NUMNODES relative to the inclusion of linux/nodemask.h, and requires powerpc to grow a new header. The dependency on NUMA_KEEP_MEMINFO for DEV_DAX_HMEM_DEVICES is invalid now that the symbol is properly exported / stubbed in all combinations of CONFIG_NUMA_KEEP_MEMINFO and CONFIG_MEMORY_HOTPLUG. [dan.j.williams@intel.com: v4] Link: https://lkml.kernel.org/r/160461461867.1505359.5301571728749534585.stgit@dwillia2-desk3.amr.corp.intel.com [dan.j.williams@intel.com: powerpc: fix create_section_mapping compile warning] Link: https://lkml.kernel.org/r/160558386174.2948926.2740149041249041764.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: a035b6bf863e ("mm/memory_hotplug: introduce default phys_to_target_node() implementation") Reported-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: Thomas Gleixner <tglx@linutronix.de> Reported-by: kernel test robot <lkp@intel.com> Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: https://lkml.kernel.org/r/160447639846.1133764.7044090803980177548.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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check_signature.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/io.h>
#include <linux/export.h>
/**
* check_signature - find BIOS signatures
* @io_addr: mmio address to check
* @signature: signature block
* @length: length of signature
*
* Perform a signature comparison with the mmio address io_addr. This
* address should have been obtained by ioremap.
* Returns 1 on a match.
*/
int check_signature(const volatile void __iomem *io_addr,
const unsigned char *signature, int length)
{
while (length--) {
if (readb(io_addr) != *signature)
return 0;
io_addr++;
signature++;
}
return 1;
}
EXPORT_SYMBOL(check_signature);
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