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- 28 May, 2016 1 commit
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James Hogan authored
Add field definitions for some of the 64-bit specific Hardware page Table Walker (HTW) register fields in PWSize and PWCtl, in preparation for fixing the 64-bit HTW configuration. Also print these fields out along with the others in print_htw_config(). Signed-off-by:
James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13363/ Signed-off-by:
Ralf Baechle <ralf@linux-mips.org>
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- 13 May, 2016 10 commits
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Paul Burton authored
XPA kernels hardcode for the presence of RIXI - the PTE format & its handling presume RI & XI bits. Make this dependence explicit by panicing if we run on a system that violates it. Signed-off-by:
Paul Burton <paul.burton@imgtec.com> Reviewed-by:
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James Hogan authored
Performing an MTHC0 instruction without XPA being present will trigger a reserved instruction exception, therefore conditionalise the use of this instruction when building TLB handlers (build_update_entries()), and in __update_tlb(). This allows an XPA kernel to run on non XPA hardware without that instruction implemented, just like it can run on XPA capable hardware without XPA in use (with the noxpa kernel argument) or with XPA not configured in hardware. [paul.burton@imgtec.com: - Rebase atop other TLB work. - Add "mm" to subject. - Handle the __kmap_pgprot case.] Fixes: c5b36783 ("MIPS: Add support for XPA.") Signed-off-by:
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Paul Burton authored
We can simplify build_update_entries by unifying the code for the 36 bit physical addressing with MIPS32 case with the general case, by using pte_off_ variables in all cases & handling the trivial _PAGE_GLOBAL_SHIFT == 0 case in build_convert_pte_to_entrylo. This leaves XPA as the only special case. Signed-off-by:
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Paul Burton authored
The XPA case in iPTE_SW or's in software mode bits to the pte_low value (which is what actually ends up in the high 32 bits of EntryLo...). It does this presuming that only bits in the upper 16 bits of the 32 bit pte_low value will be set. Make this assumption explicit with a BUG_ON. A similar assumption is made for the hardware mode bits, which are or'd in with a single ori instruction. Make that assumption explicit with a BUG_ON too. Signed-off-by:
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Paul Burton authored
Rather than hardcode a scratch register for the XPA case in iPTE_SW, pass one through from the work registers allocated by the caller. This allows for the XPA path to function correctly regardless of the work registers in use. Without doing this there are cases (where KScratch registers are unavailable) in which iPTE_SW will incorrectly clobber $1 despite it already being in use for the PTE or PTE pointer. Signed-off-by:
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James Hogan authored
For XPA kernels build_update_entries() uses $1 (at) as a scratch register, but doesn't arrange for it to be preserved, so it will always be clobbered by the TLB refill exception. Although this register normally has a very short lifetime that doesn't cross memory accesses, TLB refills due to instruction fetches (either on a page boundary or after preemption) could clobber live data, and its easy to reproduce the clobber with a little bit of assembler code. Note that the use of a hardware page table walker will partly mask the problem, as the TLB refill handler will not always be invoked. This is fixed by avoiding the use of the extra scratch register. The pte_high parts (going into the lower half of the EntryLo registers) are loaded and manipulated separately so as to keep the PTE pointer around for the other halves (instead of storing in the scratch register), and the pte_low parts (going into the high half of the EntryLo registers) are masked with 0x00ffffff using an ext instruction (instead of loading 0x00ffffff into the scratch register and AND'ing). [paul.burton@imgtec.com: - Rebase atop other TLB work. - Use ext instead of an sll, srl sequence. - Use cpu_has_xpa instead of #ifdefs. - Modify commit subject to include "mm".] Fixes: c5b36783 ("MIPS: Add support for XPA.") Signed-off-by:
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Paul Burton authored
There are 2 distinct cases in which a kernel for a MIPS32 CPU (CONFIG_CPU_MIPS32=y) may use 64 bit physical addresses (CONFIG_PHYS_ADDR_T_64BIT=y): - 36 bit physical addressing as used by RMI Alchemy & Netlogic XLP/XLR CPUs. - MIPS32r5 eXtended Physical Addressing (XPA). These 2 cases are distinct in that they require different behaviour from the kernel - the EntryLo registers have different formats. Until Linux v4.1 we only supported the first case, with code conditional upon the 2 aforementioned Kconfig variables being set. Commit c5b36783 ("MIPS: Add support for XPA.") added support for the second case, but did so by modifying the code that existed for the first case rather than treating the 2 cases as distinct. Since the EntryLo registers have different formats this breaks the 36 bit Alchemy/XLP/XLR case. Fix this by splitting the 2 cases, with XPA cases now being conditional upon CONFIG_XPA and the non-XPA case matching the code as it existed prior to commit c5b36783 ("MIPS: Add support for XPA."). Signed-off-by:Manuel Lauss <manuel.lauss@gmail.com> Tested-by:
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Paul Burton authored
Ever since support for RI/XI was implemented by commit 6dd9344c ("MIPS: Implement Read Inhibit/eXecute Inhibit") we've had a mixture of _PAGE_READ & _PAGE_NO_READ bits. Rather than keep both around, switch away from using _PAGE_READ to determine page presence & instead invert the use to _PAGE_NO_READ. Wherever we formerly had no definition for _PAGE_NO_READ, change what was _PAGE_READ to _PAGE_NO_READ. The end result is that we consistently use _PAGE_NO_READ to determine whether a page is readable, regardless of whether RI/XI is implemented. Signed-off-by:
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James Hogan authored
The hardware page table walker (HTW) configuration is broken on XPA kernels where XPA couldn't be enabled (either nohtw or the hardware doesn't support it). This is because the PWSize.PTEW field (PTE width) was only set to 8 bytes (an extra shift of 1) in config_htw_params() if PageGrain.ELPA (enable large physical addressing) is set. On an XPA kernel though the size of PTEs is fixed at 8 bytes regardless of whether XPA could actually be enabled. Fix the initialisation of this field based on sizeof(pte_t) instead. Fixes: c5b36783 ("MIPS: Add support for XPA.") Signed-off-by:
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Huacai Chen authored
Loongson-3A R2 has pwbase/pwfield/pwsize/pwctl registers in CP0 (this is very similar to HTW) and lwdir/lwpte/lddir/ldpte instructions which can be used for fast TLB refill. [ralf@linux-mips.org: Resolve conflict.] Signed-off-by:
Huacai Chen <chenhc@lemote.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Steven J . Hill <sjhill@realitydiluted.com> Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12754/ Signed-off-by:
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- 03 Apr, 2016 1 commit
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Adam Buchbinder authored
Signed-off-by:
Adam Buchbinder <adam.buchbinder@gmail.com> Cc: linux-mips@linux-mips.org Cc: trivial@kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12617/ Signed-off-by:
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- 24 Jan, 2016 1 commit
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Huacai Chen authored
Commit be0c37c9 (MIPS: Rearrange PTE bits into fixed positions.) defines fixed PTE bits for MIPS R2. Then, commit d7b63141 (MIPS: pgtable-bits: Fix XPA damage to R6 definitions.) adds the MIPS R6 definitions in the same way as MIPS R2. But some R6 #ifdefs in the later commit are missing, so in this patch I fix that. Signed-off-by:
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- 16 Jan, 2016 1 commit
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Kirill A. Shutemov authored
With new refcounting we don't need to mark PMDs splitting. Let's drop code to handle this. pmdp_splitting_flush() is not needed too: on splitting PMD we will do pmdp_clear_flush() + set_pte_at(). pmdp_clear_flush() will do IPI as needed for fast_gup. Signed-off-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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- 11 Nov, 2015 5 commits
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Paul Burton authored
Extend the existing support for Hardware Table Walking (HTW) to MIPS64 systems by supporting PMDs & setting the pointer size bit in PWSize, then ceasing to blacklist HTW on MIPS64 systems. Signed-off-by:
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Paul Burton authored
Commit 748e787e ("MIPS: Optimize TLB refill for RI/XI configurations.") stopped explicitly clearing the bits used by software in PTEs by making use of a rotate instruction that rotates them into the fill bits of the Entry{Lo,Hi} register. This can only work if there are actually enough fill bits in the register to cover the software maintained bits, otherwise we end up writing those bits into the upper bits of the PFN or PFNX field of the Entry{Lo,Hi} register. Fix this by detecting the number of fill bits present in the Entry{Lo,Hi} registers & explicitly clearing the software bits where necessary. Signed-off-by:
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Paul Burton authored
The code in build_update_entries for 64 bit physical addresses on a MIPS64 CPU and 32 bit physical addresses on a MIPS32 CPU is now identical, with the exception of r4k bug workaround in the latter which would simply not apply to the former. Remove the duplication and some Signed-off-by:
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Paul Burton authored
The cpu_has_rixi cases in build_update_entries are now identical to the non-RIXI cases with the one exception of the r45k_bvahwbug case which is hardcoded as never happening anyway & presumably was either missed from the RIXI path or would never happen on a CPU with RIXI support. Remove the redundant checks & duplication. Signed-off-by:
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Paul Burton authored
Make use of build_convert_pte_to_entrylo in the RIXI cases within build_update_entries rather than open-coding it 4 times. Signed-off-by:
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- 21 Jun, 2015 3 commits
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James Hogan authored
Commit c5b36783 ("MIPS: Add support for XPA.") added generation of a shift by _PAGE_PRESENT_SHIFT in build_pte_present() and build_pte_writable(), however except for the XPA case this is always zero making it unnecessary. Make the shift conditional upon _PAGE_PRESENT_SHIFT being non-zero to save an instruction in those cases. Fixes: c5b36783 ("MIPS: Add support for XPA.") Signed-off-by:
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James Hogan authored
Commit c5b36783 ("MIPS: Add support for XPA.") changed build_pte_present() and build_pte_writable() to assume a constant offset of _PAGE_READ and _PAGE_WRITE relative to _PAGE_PRESENT, however this is no longer true for some MIPS32R2 builds since commit be0c37c9 ("MIPS: Rearrange PTE bits into fixed positions.") which moved the _PAGE_READ PTE bit away from the _PAGE_PRESENT bit, with the _PAGE_WRITE bit falling into its place. Make use of the _PAGE_READ and _PAGE_WRITE definitions to calculate the correct mask to apply instead of hard coding 3 (for _PAGE_PRESENT | _PAGE_READ) or 5 (for _PAGE_PRESENT | _PAGE_WRITE). Fixes: c5b36783 ("MIPS: Add support for XPA.") Signed-off-by:
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Paul Gortmaker authored
We removed __cpuinit support (leaving no-op stubs) quite some time ago. However a new instance was added in commit c5b36783 ("MIPS: Add support for XPA.") Since we want to clobber the stubs soon, get this removed now. Signed-off-by:
Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Steven J. Hill <Steven.Hill@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/9894/ Signed-off-by:
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- 16 Jun, 2015 1 commit
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Paul Gortmaker authored
We removed __cpuinit support (leaving no-op stubs) quite some time ago. However a new instance was added in commit c5b36783 ("MIPS: Add support for XPA.") Since we want to clobber the stubs soon, get this removed now. Cc: Steven J. Hill <Steven.Hill@imgtec.com> Cc: linux-mips@linux-mips.org Signed-off-by:
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- 10 Apr, 2015 1 commit
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Ralf Baechle authored
For a discussion, see http://patchwork.linux-mips.org/patch/9539/. This reverts commit 625c0a21.
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- 01 Apr, 2015 1 commit
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Joshua Kinard authored
This allows the kernel to correctly detect an R16000 MIPS CPU on systems that have those. Otherwise, such systems will detect the CPU as an R14000, due to similarities in the CPU PRId value. Signed-off-by:
Joshua Kinard <kumba@gentoo.org> Cc: Linux MIPS List <linux-mips@linux-mips.org> Patchwork: https://patchwork.linux-mips.org/patch/9092/ Signed-off-by:
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- 19 Mar, 2015 1 commit
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Steven J. Hill authored
Add support for extended physical addressing (XPA) so that 32-bit platforms can access equal to or greater than 40 bits of physical addresses. NOTE: 1) XPA and EVA are not the same and cannot be used simultaneously. 2) If you configure your kernel for XPA, the PTEs and all address sizes become 64-bit. 3) Your platform MUST have working HIGHMEM support. Signed-off-by:Steven J. Hill <Steven.Hill@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9355/ Signed-off-by:
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- 18 Mar, 2015 1 commit
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Steven J. Hill authored
This patch rearranges the PTE bits into fixed positions for R2 and later cores. In the past, the TLB handling code did runtime checking of RI/XI and adjusted the shifts and rotates in order to fit the largest PFN value into the PTE. The checking now occurs when building the TLB handler, thus eliminating those checks. These new arrangements also define the largest possible PFN value that can fit in the PTE. HUGE page support is only available for 64-bit cores. Layouts of the PTE bits are now: 64-bit, R1 or earlier: CCC D V G [S H] M A W R P 32-bit, R1 or earler: CCC D V G M A W R P 64-bit, R2 or later: CCC D V G RI/R XI [S H] M A W P 32-bit, R2 or later: CCC D V G RI/R XI M A W P [ralf@linux-mips.org: Fix another build error *rant* *rant*] Signed-off-by:
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- 17 Feb, 2015 1 commit
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Leonid Yegoshin authored
MIPS uses the cpu_has_mips_r2_exec_hazard macro to determine whether the EHB instruction is available or not. This is necessary for MIPS R6 which also supports the EHB instruction. Signed-off-by:
Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by:
Markos Chandras <markos.chandras@imgtec.com>
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- 16 Feb, 2015 1 commit
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Leonid Yegoshin authored
Add a CPU_QEMU_GENERIC case to various switch statements. Signed-off-by:
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- 27 Nov, 2014 1 commit
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Leonid Yegoshin authored
There is a potential race when probing the TLB in TLBL/M/S exception handlers for a matching entry. Between the time we hit a TLBL/S/M exception and the time we get to execute the TLBP instruction, the HTW may have replaced the TLB entry we are interested in hence the TLB probe may fail. However, in the existing handlers, we never checked the status of the TLBP (ie check the result in the C0/Index register). We fix this by adding such a check when the core implements the HTW. If we couldn't find a matching entry, we return back and try again. Signed-off-by:
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- 24 Nov, 2014 1 commit
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Ralf Baechle authored
Signed-off-by:
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- 22 Oct, 2014 1 commit
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David Daney authored
In commit 8393c524 (MIPS: tlbex: Fix a missing statement for HUGETLB), the TLB Refill handler was fixed so that non-OCTEON targets would work properly with huge pages. The change was incorrect in that it broke the OCTEON case. The problem is shown here: xxx0: df7a0000 ld k0,0(k1) . . . xxxc0: df610000 ld at,0(k1) xxxc4: 335a0ff0 andi k0,k0,0xff0 xxxc8: e825ffcd bbit1 at,0x5,0x0 xxxcc: 003ad82d daddu k1,at,k0 . . . In the non-octeon case there is a destructive test for the huge PTE bit, and then at 0, $k0 is reloaded (that is what the 8393c524 patch added). In the octeon case, we modify k1 in the branch delay slot, but we never need k0 again, so the new load is not needed, but since k1 is modified, if we do the load, we load from a garbage location and then get a nested TLB Refill, which is seen in userspace as either SIGBUS or SIGSEGV (depending on the garbage). The real fix is to only do this reloading if it is needed, and never where it is harmful. Signed-off-by:
David Daney <david.daney@cavium.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: stable@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8151/ Signed-off-by:
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- 01 Aug, 2014 3 commits
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Leonid Yegoshin authored
Use the regular tlb_do_page_fault_0 (no write) handler to handle the RI and XI exceptions. Also skip the RI/XI validation check on TLB load handler since it's redundant when the CPU has unique RI/XI exceptions. Singed-off-by:
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Markos Chandras authored
The Hardware Page Table Walker aims to speed up TLB refill exceptions by handling them in the hardware level instead of having a software TLB refill handler. However, a TLB refill exception can still be thrown in certain cases such as, synchronus exceptions, or address translation or memory errors during the HTW operation. As a result of which, HTW must not be considered a complete replacement for the TLB refill software handler, but rather a fast-path for it. For HTW to work, the PWBase register must contain the task's page global directory address so the HTW will kick in on TLB refill exceptions. Due to HTW being a separate engine embedded deep in the CPU pipeline, we need to restart the HTW everytime a PTE changes to avoid HTW fetching a old entry from the page tables. It's also necessary to restart the HTW on context switches to prevent it from fetching a page from the previous process. Finally, since HTW is using the entryhi register to write the translations to the TLB, it's necessary to stop the HTW whenever the entryhi changes (eg for tlb probe perations) and enable it back afterwards. == Performance == The following trivial test was used to measure the performance of the HTW. Using the same root filesystem, the following command was used to measure the number of tlb refill handler executions with and without (using 'nohtw' kernel parameter) HTW support. The kernel was modified to use a scratch register as a counter for the TLB refill exceptions. find /usr -type f -exec ls -lh {} \; HTW Enabled: TLB refill exceptions: 12306 HTW Disabled: TLB refill exceptions: 17805 Signed-off-by: -
Leonid Yegoshin authored
Commit Commit 1d40cfcd Author: Ralf Baechle <ralf@linux-mips.org> Date: Fri Jul 15 15:23:23 2005 +0000 Avoid SMP cacheflushes. This is a minor optimization of startup but will also avoid smp_call_function from doing stupid things when called from a CPU that is not yet marked online. missed an appropriate cache flush of TLB refill handler because that time it was at fixed location CAC_BASE. After years the refill handler in EBASE vector is not at that location and can be allocated in some another memory and needs I-cache sync as other TLB exception vectors. Besides that, the new function - local_flash_icache_range() was introduced to avoid SMP cacheflushes. Signed-off-by:
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- 30 Jul, 2014 1 commit
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Huacai Chen authored
In commit 2c8c53e2 (MIPS: Optimize TLB handlers for Octeon CPUs) build_r4000_tlb_refill_handler() is modified. But it doesn't compatible with the original code in HUGETLB case. Because there is a copy & paste error and one line of code is missing. It is very easy to produce a bug with LTP's hugemmap05 test. Signed-off-by:
Binbin Zhou <zhoubb@lemote.com> Cc: <stable@vger.kernel.org> Cc: John Crispin <john@phrozen.org> Cc: Steven J. Hill <Steven.Hill@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Patchwork: https://patchwork.linux-mips.org/patch/7496/ Signed-off-by:
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- 02 Jun, 2014 1 commit
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David Daney authored
For para-virtualized guests running under KVM or other equivalent hypervisor. Signed-off-by:
Andreas Herrmann <andreas.herrmann@caviumnetworks.com> Cc: linux-mips@linux-mips.org Cc: James Hogan <james.hogan@imgtec.com> Cc: kvm@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/7004/ Signed-off-by:
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- 30 May, 2014 1 commit
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David Daney authored
The fast handler only supports 64-bit kernels. Signed-off-by:
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- 14 May, 2014 1 commit
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Steven J. Hill authored
Commit f4ae17aa [MIPS: mm: Use scratch for PGD when !CONFIG_MIPS_PGD_C0_CONTEXT] broke microMIPS kernel builds. This patch refactors that code similar to what was done for the 'clear_page' and 'copy_page' functions. Signed-off-by:
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- 31 Mar, 2014 1 commit
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Huacai Chen authored
Basic Loongson-3 CPU support include CPU probing and TLB/cache initializing. Signed-off-by:
Hongliang Tao <taohl@lemote.com> Signed-off-by:
Hua Yan <yanh@lemote.com> Tested-by:
Alex Smith <alex.smith@imgtec.com> Reviewed-by:
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