From 91dfc423cc8cfd399fb308a837102a7ab7fa067e Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Tue, 2 Feb 2010 08:52:20 -0800 Subject: MIPS: 64-bit: Detect virtual memory size Linux kernel 2.6.32 and later allocate address space from the top of the kernel virtual memory address space. This patch implements virtual memory size detection for 64 bit MIPS CPUs to avoid resulting crashes. Signed-off-by: Guenter Roeck Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/935/ Reviewed-by: David Daney Signed-off-by: Ralf Baechle --- arch/mips/kernel/cpu-probe.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'arch/mips/kernel') diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index 80e202eca056..9c187a64649b 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -284,6 +284,15 @@ static inline int __cpu_has_fpu(void) return ((cpu_get_fpu_id() & 0xff00) != FPIR_IMP_NONE); } +static inline void cpu_probe_vmbits(struct cpuinfo_mips *c) +{ +#ifdef __NEED_VMBITS_PROBE + write_c0_entryhi(0x3ffffffffffff000ULL); + back_to_back_c0_hazard(); + c->vmbits = fls64(read_c0_entryhi() & 0x3ffffffffffff000ULL); +#endif +} + #define R4K_OPTS (MIPS_CPU_TLB | MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE \ | MIPS_CPU_COUNTER) @@ -969,6 +978,8 @@ __cpuinit void cpu_probe(void) c->srsets = ((read_c0_srsctl() >> 26) & 0x0f) + 1; else c->srsets = 1; + + cpu_probe_vmbits(c); } __cpuinit void cpu_report(void) -- cgit v1.2.3