From e7bc8557428f069eaa613b3676ea6931c0f7fe43 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Fri, 2 Jun 2017 15:38:01 -0700 Subject: MIPS: Add CPU shared FTLB feature detection Some systems share FTLB RAMs or entries between sibling CPUs (ie. hardware threads, or VP(E)s, within a core). These properties require kernel handling in various places. As a start this patch introduces cpu_has_shared_ftlb_ram & cpu_has_shared_ftlb_entries feature macros which we set appropriately for I6400 & I6500 CPUs. Further patches will make use of these macros as appropriate. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16202/ Signed-off-by: Ralf Baechle --- arch/mips/include/asm/cpu-features.h | 41 ++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'arch/mips/include/asm/cpu-features.h') diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h index 494d38274142..d6ea8e7c5107 100644 --- a/arch/mips/include/asm/cpu-features.h +++ b/arch/mips/include/asm/cpu-features.h @@ -487,6 +487,47 @@ # define cpu_has_perf (cpu_data[0].options & MIPS_CPU_PERF) #endif +#if defined(CONFIG_SMP) && defined(__mips_isa_rev) && (__mips_isa_rev >= 6) +/* + * Some systems share FTLB RAMs between threads within a core (siblings in + * kernel parlance). This means that FTLB entries may become invalid at almost + * any point when an entry is evicted due to a sibling thread writing an entry + * to the shared FTLB RAM. + * + * This is only relevant to SMP systems, and the only systems that exhibit this + * property implement MIPSr6 or higher so we constrain support for this to + * kernels that will run on such systems. + */ +# ifndef cpu_has_shared_ftlb_ram +# define cpu_has_shared_ftlb_ram \ + (current_cpu_data.options & MIPS_CPU_SHARED_FTLB_RAM) +# endif + +/* + * Some systems take this a step further & share FTLB entries between siblings. + * This is implemented as TLB writes happening as usual, but if an entry + * written by a sibling exists in the shared FTLB for a translation which would + * otherwise cause a TLB refill exception then the CPU will use the entry + * written by its sibling rather than triggering a refill & writing a matching + * TLB entry for itself. + * + * This is naturally only valid if a TLB entry is known to be suitable for use + * on all siblings in a CPU, and so it only takes effect when MMIDs are in use + * rather than ASIDs or when a TLB entry is marked global. + */ +# ifndef cpu_has_shared_ftlb_entries +# define cpu_has_shared_ftlb_entries \ + (current_cpu_data.options & MIPS_CPU_SHARED_FTLB_ENTRIES) +# endif +#endif /* SMP && __mips_isa_rev >= 6 */ + +#ifndef cpu_has_shared_ftlb_ram +# define cpu_has_shared_ftlb_ram 0 +#endif +#ifndef cpu_has_shared_ftlb_entries +# define cpu_has_shared_ftlb_entries 0 +#endif + /* * Guest capabilities */ -- cgit v1.2.3 From 8d1630f13754f1435d3ea7078829121c52f38d15 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Tue, 23 May 2017 13:37:05 +0100 Subject: MIPS: MIPS16e2: Identify ASE presence Identify the presence of the MIPS16e2 ASE as per the architecture specification[1], by checking for CP0 Config5.CA2 bit being 1[2]. References: [1] "MIPS32 Architecture for Programmers: MIPS16e2 Application-Specific Extension Technical Reference Manual", Imagination Technologies Ltd., Document Number: MD01172, Revision 01.00, April 26, 2016, Section 1.2 "Software Detection of the ASE", p. 5 [2] "MIPS32 interAptiv Multiprocessing System Software User's Manual", Imagination Technologies Ltd., Document Number: MD00904, Revision 02.01, June 15, 2016, Section 2.2.1.6 "Device Configuration 5 -- Config5 (CP0 Register 16, Select 5)", pp. 71-72 Signed-off-by: Maciej W. Rozycki Reviewed-by: James Hogan Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16094/ Signed-off-by: Ralf Baechle --- arch/mips/include/asm/cpu-features.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/mips/include/asm/cpu-features.h') diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h index d6ea8e7c5107..8baa9033b181 100644 --- a/arch/mips/include/asm/cpu-features.h +++ b/arch/mips/include/asm/cpu-features.h @@ -138,6 +138,9 @@ #ifndef cpu_has_mips16 #define cpu_has_mips16 (cpu_data[0].ases & MIPS_ASE_MIPS16) #endif +#ifndef cpu_has_mips16e2 +#define cpu_has_mips16e2 (cpu_data[0].ases & MIPS_ASE_MIPS16E2) +#endif #ifndef cpu_has_mdmx #define cpu_has_mdmx (cpu_data[0].ases & MIPS_ASE_MDMX) #endif -- cgit v1.2.3