With a 32-bit kernel running on 64-bit MIPS hardware the hardcoded value
of `cpu_vmbits' only records the size of compatibility useg and does not
reflect the size of native xuseg or the complete range of values allowed
in the VPN2 field of TLB entries.
An upcoming change will need the actual VPN2 value range permitted even
in 32-bit kernel configurations, so always include the `vmbits' member
in `struct cpuinfo_mips' and probe for SEGBITS when running on 64-bit
hardware and resorting to the currently hardcoded value of 31 on 32-bit
processors. No functional change for users of `cpu_vmbits'.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Some of the cache functions are declared only for their callers, e.g.
arch/mips/mm/c-r3k.c:28:15: error: no previous prototype for 'r3k_cache_size' [-Werror=missing-prototypes]
arch/mips/mm/c-r3k.c:63:15: error: no previous prototype for 'r3k_cache_lsize' [-Werror=missing-prototypes]
arch/mips/mm/c-r4k.c:1703:6: error: no previous prototype for 'r4k_cache_init' [-Werror=missing-prototypes]
arch/mips/mm/sc-mips.c:255:5: error: no previous prototype for 'mips_sc_init' [-Werror=missing-prototypes]
Move all the declarations to asm/cache.h and asm/r4kcache.h where they
can be seen by the function definitions.
Link: https://lkml.kernel.org/r/20231204115710.2247097-13-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Stephen Rothwell <sfr@rothwell.id.au>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
BMIPS is one of the few platforms that do change the exception base.
After commit 2dcb396454 ("memblock: do not start bottom-up allocations
with kernel_end") we started seeing BMIPS boards fail to boot with the
built-in FDT being corrupted.
Before the cited commit, early allocations would be in the [kernel_end,
RAM_END] range, but after commit they would be within [RAM_START +
PAGE_SIZE, RAM_END].
The custom exception base handler that is installed by
bmips_ebase_setup() done for BMIPS5000 CPUs ends-up trampling on the
memory region allocated by unflatten_and_copy_device_tree() thus
corrupting the FDT used by the kernel.
To fix this, we need to perform an early reservation of the custom
exception space. Additional we reserve the first 4k (1k for R3k) for
either normal exception vector space (legacy CPUs) or special vectors
like cache exceptions.
Huge thanks to Serge for analysing and proposing a solution to this
issue.
Fixes: 2dcb396454 ("memblock: do not start bottom-up allocations with kernel_end")
Reported-by: Kamal Dasu <kdasu.kdev@gmail.com>
Debugged-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Running a kernel on a R3k of machine definitly will never see one of
the newer CPU cores. And since R3k system usually are low on memory
we could save quite some kbytes:
text data bss dec hex filename
15070 88 32 15190 3b56 arch/mips/kernel/cpu-probe.o
844 4 16 864 360 arch/mips/kernel/cpu-r3k-probe.o
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
