- 26 May, 2020 18 commits
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Christophe Leroy authored
At the time being, 512k huge pages are handled through hugepd page tables. The PMD entry is flagged as a hugepd pointer and it means that only 512k hugepages can be managed in that 4M block. However, the hugepd table has the same size as a normal page table, and 512k entries can therefore be nested with normal pages. On the 8xx, TLB loading is performed by software and allthough the page tables are organised to match the L1 and L2 level defined by the HW, all TLB entries have both L1 and L2 independent entries. It means that even if two TLB entries are associated with the same PMD entry, they can be loaded with different values in L1 part. The L1 entry contains the page size (PS field): - 00 for 4k and 16 pages - 01 for 512k pages - 11 for 8M pages By adding a flag for hugepages in the PTE (_PAGE_HUGE) and copying it into the lower bit of PS, we can then manage 512k pages with normal page tables: - PMD entry has PS=11 for 8M pages - PMD entry has PS=00 for other pages. As a PMD entry covers 4M areas, a PMD will either point to a hugepd table having a single entry to an 8M page, or the PMD will point to a standard page table which will have either entries to 4k or 16k or 512k pages. For 512k pages, as the L1 entry will not know it is a 512k page before the PTE is read, there will be 128 entries in the PTE as if it was 4k pages. But when loading the TLB, it will be flagged as a 512k page. Note that we can't use pmd_ptr() in asm/nohash/32/pgtable.h because it is not defined yet. In ITLB miss, we keep the possibility to opt it out as when kernel text is pinned and no user hugepages are used, we can save several instruction by not using r11. In DTLB miss, that's just one instruction so it's not worth bothering with it. Signed-off-by:
Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/002819e8e166bf81d24b24782d98de7c40905d8f.1589866984.git.christophe.leroy@csgroup.eu
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Christophe Leroy authored
Prepare ITLB handler to handle _PAGE_HUGE when CONFIG_HUGETLBFS is enabled. This means that the L1 entry has to be kept in r11 until L2 entry is read, in order to insert _PAGE_HUGE into it. Also move pgd_offset helpers before pte_update() as they will be needed there in next patch. Signed-off-by:
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Christophe Leroy authored
CONFIG_8xx_COPYBACK was there to help disabling copyback cache mode for debuging hardware. But nobody will design new boards with 8xx now. All 8xx platforms select it, so make it the default and remove the option. Also remove the Mx_RESETVAL values which are pretty useless and hide the real value while reading code. Signed-off-by:
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Christophe Leroy authored
Commit 55c8fc3f ("powerpc/8xx: reintroduce 16K pages with HW assistance") redefined pte_t as a struct of 4 pte_basic_t, because in 16K pages mode there are four identical entries in the page table. But hugepd entries for 8M pages require only one entry of size pte_basic_t. So there is no point in creating a cache for 4 entries page tables. Calculate PTE_T_ORDER using the size of pte_basic_t instead of pte_t. Define specific huge_pte helpers (set_huge_pte_at(), huge_pte_clear(), huge_ptep_set_wrprotect()) to write the pte in a single entry instead of using set_pte_at() which writes 4 identical entries in 16k pages mode. Also make sure that __ptep_set_access_flags() properly handle the huge_pte case. Define set_pte_filter() inline otherwise GCC doesn't inline it anymore because it is now used twice, and that gives a pretty suboptimal code because of pte_t being a struct of 4 entries. Those functions are also used for 512k pages which only require one entry as well allthough replicating it four times was harmless as 512k pages entries are spread every 128 bytes in the table. Signed-off-by:
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Christophe Leroy authored
pte_update() is a bit special for the 8xx. At the time being, that's an #ifdef inside the nohash/32 pte_update(). As we are going to make it even more special in the coming patches, create a dedicated version for pte_update() for 8xx. Signed-off-by:
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Christophe Leroy authored
PPC64 takes 3 additional parameters compared to PPC32: - mm - address - huge These 3 parameters will be needed in order to perform different action depending on the page size on the 8xx. Make pte_update() prototype identical for PPC32 and PPC64. This allows dropping an #ifdef in huge_ptep_get_and_clear(). Signed-off-by:
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Christophe Leroy authored
On PPC32, __ptep_test_and_clear_young() takes the mm->context.id In preparation of standardising pte_update() params between PPC32 and PPC64, __ptep_test_and_clear_young() need mm instead of mm->context.id Replace context param by mm. Signed-off-by:
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Christophe Leroy authored
When CONFIG_PTE_64BIT is set, pte_update() operates on 'unsigned long long' When CONFIG_PTE_64BIT is not set, pte_update() operates on 'unsigned long' In asm/page.h, we have pte_basic_t which is 'unsigned long long' when CONFIG_PTE_64BIT is set and 'unsigned long' otherwise. Refactor pte_update() using pte_basic_t. While we are at it, drop the comment on 44x which is not applicable to book3s version of pte_update(). Signed-off-by:
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Christophe Leroy authored
When CONFIG_PTE_64BIT is set, pte_update() operates on 'unsigned long long' When CONFIG_PTE_64BIT is not set, pte_update() operates on 'unsigned long' In asm/page.h, we have pte_basic_t which is 'unsigned long long' when CONFIG_PTE_64BIT is set and 'unsigned long' otherwise. Refactor pte_update() using pte_basic_t. Signed-off-by:
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Christophe Leroy authored
Only 40x still uses PTE_ATOMIC_UPDATES. 40x cannot not select CONFIG_PTE64_BIT. Drop handling of PTE_ATOMIC_UPDATES: - In nohash/64 - In nohash/32 for CONFIG_PTE_64BIT Keep PTE_ATOMIC_UPDATES only for nohash/32 for !CONFIG_PTE_64BIT Signed-off-by:
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Christophe Leroy authored
Setting init mem to NX shall depend on sinittext being mapped by block, not on stext being mapped by block. Setting text and rodata to RO shall depend on stext being mapped by block, not on sinittext being mapped by block. Fixes: 63b2bc61 ("powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX") Cc: stable@vger.kernel.org Signed-off-by:
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Christophe Leroy authored
Allocate static page tables for the fixmap area. This allows setting mappings through page tables before memblock is ready. That's needed to use early_ioremap() early and to use standard page mappings with fixmap. Signed-off-by:
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Christophe Leroy authored
Mapping RO data as ROX is not an issue since that data cannot be modified to introduce an exploit. PPC64 accepts to have RO data mapped ROX, as a trade off between kernel size and strictness of protection. On PPC32, kernel size is even more critical as amount of memory is usually small. Depending on the number of available IBATs, the last IBATs might overflow the end of text. Only warn if it crosses the end of RO data. Signed-off-by:
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Christophe Leroy authored
The 8xx is about to map kernel linear space and IMMR using huge pages. In order to display those pages properly, ptdump needs to handle hugepd tables at PGD level. For the time being do it only at PGD level. Further patches may add handling of hugepd tables at lower level for other platforms when needed in the future. Signed-off-by:
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Christophe Leroy authored
In order to properly display information regardless of the page size, it is necessary to take into account real page size. Fixes: cabe8138 ("powerpc: dump as a single line areas mapping a single physical page.") Cc: stable@vger.kernel.org Signed-off-by:
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Christophe Leroy authored
Display BAT flags the same way as page flags: rwx and wimg Signed-off-by:
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Christophe Leroy authored
Display the size of areas mapped with BATs. For that, the size display for pages is refactorised. Signed-off-by:
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Christophe Leroy authored
For platforms using shared.c (4xx, Book3e, Book3s/32), also handle the _PAGE_COHERENT flag which corresponds to the M bit of the WIMG flags. Signed-off-by:
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- 20 May, 2020 6 commits
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Christophe Leroy authored
In order to alloc sub-arches to alloc KASAN regions using optimised methods (Huge pages on 8xx, BATs on BOOK3S, ...), declare kasan_init_region() weak. Also make kasan_init_shadow_page_tables() accessible from outside, so that it can be called from the specific kasan_init_region() functions if needed. And populate remaining KASAN address space only once performed the region mapping, to allow 8xx to allocate hugepd instead of standard page tables for mapping via 8M hugepages. Signed-off-by:
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Christophe Leroy authored
kasan_remap_early_shadow_ro() and kasan_unmap_early_shadow_vmalloc() are both updating the early shadow mapping: the first one sets the mapping read-only while the other clears the mapping. Refactor and create kasan_update_early_region() Signed-off-by:
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Christophe Leroy authored
Commit 45ff3c55 ("powerpc/kasan: Fix parallel loading of modules.") added spinlocks to manage parallele module loading. Since then commit 47febbee ("powerpc/32: Force KASAN_VMALLOC for modules") converted the module loading to KASAN_VMALLOC. The spinlocking has then become unneeded and can be removed to simplify kasan_init_shadow_page_tables() Also remove inclusion of linux/moduleloader.h and linux/vmalloc.h which are not needed anymore since the removal of modules management. Signed-off-by:
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Christophe Leroy authored
Doing kasan pages allocation in MMU_init is too early, kernel doesn't have access yet to the entire memory space and memblock_alloc() fails when the kernel is a bit big. Do it from kasan_init() instead. Fixes: 2edb16ef ("powerpc/32: Add KASAN support") Cc: stable@vger.kernel.org Signed-off-by:
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Christophe Leroy authored
At the time being, KASAN_SHADOW_END is 0x100000000, which is 0 in 32 bits representation. This leads to a couple of issues: - kasan_remap_early_shadow_ro() does nothing because the comparison k_cur < k_end is always false. - In ptdump, address comparison for markers display fails and the marker's name is printed at the start of the KASAN area instead of being printed at the end. However, there is no need to shadow the KASAN shadow area itself, so the KASAN shadow area can stop shadowing memory at the start of itself. With a PAGE_OFFSET set to 0xc0000000, KASAN shadow area is then going from 0xf8000000 to 0xff000000. Fixes: cbd18991 ("powerpc/mm: Fix an Oops in kasan_mmu_init()") Cc: stable@vger.kernel.org Signed-off-by:
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Christophe Leroy authored
In case (k_start & PAGE_MASK) doesn't equal (kstart), 'va' will never be NULL allthough 'block' is NULL Check the return of memblock_alloc() directly instead of the resulting address in the loop. Fixes: 509cd3f2 ("powerpc/32: Simplify KASAN init") Signed-off-by:
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- 18 May, 2020 16 commits
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Ravi Bangoria authored
Add support for 2nd DAWR in xmon. With this, we can have two simultaneous breakpoints from xmon. Signed-off-by:
Ravi Bangoria <ravi.bangoria@linux.ibm.com> Signed-off-by:
Michael Neuling <mikey@neuling.org> Link: https://lore.kernel.org/r/20200514111741.97993-17-ravi.bangoria@linux.ibm.com
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Ravi Bangoria authored
Xmon allows overwriting breakpoints because it's supported by only one DAWR. But with multiple DAWRs, overwriting becomes ambiguous or unnecessary complicated. So let's not allow it. Signed-off-by:
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Ravi Bangoria authored
With Book3s DAWR, ptrace and perf watchpoints on powerpc behaves differently. Ptrace watchpoint works in one-shot mode and generates signal before executing instruction. It's ptrace user's job to single-step the instruction and re-enable the watchpoint. OTOH, in case of perf watchpoint, kernel emulates/single-steps the instruction and then generates event. If perf and ptrace creates two events with same or overlapping address ranges, it's ambiguous to decide who should single-step the instruction. Because of this issue, don't allow perf and ptrace watchpoint at the same time if their address range overlaps. Signed-off-by:
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Ravi Bangoria authored
Currently we assume that we have only one watchpoint supported by hw. Get rid of that assumption and use dynamic loop instead. This should make supporting more watchpoints very easy. With more than one watchpoint, exception handler needs to know which DAWR caused the exception, and hw currently does not provide it. So we need sw logic for the same. To figure out which DAWR caused the exception, check all different combinations of user specified range, DAWR address range, actual access range and DAWRX constrains. For ex, if user specified range and actual access range overlaps but DAWRX is configured for readonly watchpoint and the instruction is store, this DAWR must not have caused exception. Signed-off-by:
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Ravi Bangoria authored
Currently we calculate hw aligned start and end addresses manually. Replace them with builtin ALIGN_DOWN() and ALIGN() macros. So far end_addr was inclusive but this patch makes it exclusive (by avoiding -1) for better readability. Suggested-by:
Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by:
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Ravi Bangoria authored
Introduce is_ptrace_bp() function and move the check inside the function. It will be utilize more in later set of patches. Signed-off-by:
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Ravi Bangoria authored
ptrace_bps is already an array of size HBP_NUM_MAX. But we use hardcoded index 0 while fetching/updating it. Convert such code to loop over array. ptrace interface to use multiple watchpoint remains same. eg: two PPC_PTRACE_SETHWDEBUG calls will create two watchpoint if underneath hw supports it. Signed-off-by:
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Ravi Bangoria authored
So far powerpc hw supported only one watchpoint. But Power10 is introducing 2nd DAWR. Convert thread_struct->hw_brk into an array. Signed-off-by:
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Ravi Bangoria authored
Instead of disabling only first watchpoint, disable all available watchpoints while clearing dawr_force_enable. Callback function is used only for disabling watchpoint, rename it to disable_dawrs_cb(). And null_brk parameter is not really required while disabling watchpoint, remove it. Signed-off-by:
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Ravi Bangoria authored
Instead of disabling only one watchpoint, get num of available watchpoints dynamically and disable all of them. Signed-off-by:
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Ravi Bangoria authored
Introduce new parameter 'nr' to __set_breakpoint() which indicates which DAWR should be programed. Also convert current_brk variable to an array. Signed-off-by:
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Ravi Bangoria authored
Introduce new parameter 'nr' to set_dawr() which indicates which DAWR should be programed. Signed-off-by:
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Ravi Bangoria authored
User can ask for num of available watchpoints(dbginfo.num_data_bps) using ptrace(PPC_PTRACE_GETHWDBGINFO). Return actual number of available watchpoints on the machine rather than hardcoded 1. Signed-off-by:
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Ravi Bangoria authored
So far we had only one watchpoint, so we have hardcoded HBP_NUM to 1. But Power10 is introducing 2nd DAWR and thus kernel should be able to dynamically find actual number of watchpoints supported by hw it's running on. Introduce function for the same. Also convert HBP_NUM macro to HBP_NUM_MAX, which will now represent maximum number of watchpoints supported by Powerpc. Signed-off-by:
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Ravi Bangoria authored
Power10 is introducing second DAWR. Add SPRN_ macros for the same. Signed-off-by:
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Ravi Bangoria authored
Power10 is introducing second DAWR. Use real register names from ISA for current macros: s/SPRN_DAWR/SPRN_DAWR0/ s/SPRN_DAWRX/SPRN_DAWRX0/ Signed-off-by:
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