| Message ID | 20230529180023.289904-1-bjorn@kernel.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | riscv: mm: Pre-allocate PGD entries vmalloc/modules area | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/cover_letter | success | Single patches do not need cover letters |
| conchuod/tree_selection | success | Guessed tree name to be for-next at HEAD ac9a78681b92 |
| conchuod/fixes_present | success | Fixes tag not required for -next series |
| conchuod/maintainers_pattern | success | MAINTAINERS pattern errors before the patch: 6 and now 6 |
| conchuod/verify_signedoff | success | Signed-off-by tag matches author and committer |
| conchuod/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| conchuod/build_rv64_clang_allmodconfig | success | Errors and warnings before: 14 this patch: 14 |
| conchuod/module_param | success | Was 0 now: 0 |
| conchuod/build_rv64_gcc_allmodconfig | success | Errors and warnings before: 29 this patch: 29 |
| conchuod/build_rv32_defconfig | success | Build OK |
| conchuod/dtb_warn_rv64 | success | Errors and warnings before: 3 this patch: 3 |
| conchuod/header_inline | success | No static functions without inline keyword in header files |
| conchuod/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 97 lines checked |
| conchuod/build_rv64_nommu_k210_defconfig | fail | Build failed |
| conchuod/verify_fixes | success | No Fixes tag |
| conchuod/build_rv64_nommu_virt_defconfig | fail | Build failed |
Björn Töpel <bjorn@kernel.org> writes: > From: Björn Töpel <bjorn@rivosinc.com> > > The RISC-V port requires that kernel PGD entries are to be > synchronized between MMs. This is done via the vmalloc_fault() > function, that simply copies the PGD entries from init_mm to the > faulting one. > > Historically, faulting in PGD entries have been a source for both bugs > [1], and poor performance. > > One way to get rid of vmalloc faults is by pre-allocating the PGD > entries. Pre-allocating the entries potientially wastes 64 * 4K (65 on > SV39). The pre-allocation function is pulled from Jörg Rödel's x86 > work, with the addition of 3-level page tables (PMD allocations). > > The pmd_alloc() function needs the ptlock cache to be initialized > (when split page locks is enabled), so the pre-allocation is done in a > RISC-V specific pgtable_cache_init() implementation. > > Pre-allocate the kernel PGD entries for the vmalloc/modules area, but > only for 64b platforms. > > Link: https://lore.kernel.org/lkml/20200508144043.13893-1-joro@8bytes.org/ # [1] > Signed-off-by: Björn Töpel <bjorn@rivosinc.com> ...and the build was bitten by nommu [1]. I'll hold off the v2 a bit, to see if there's any other comments. Björn [1] https://patchwork.kernel.org/project/linux-riscv/patch/20230529180023.289904-1-bjorn@kernel.org/
Hi Björn,
kernel test robot noticed the following build warnings:
[auto build test WARNING on ac9a78681b921877518763ba0e89202254349d1b]
url: https://github.com/intel-lab-lkp/linux/commits/Bj-rn-T-pel/riscv-mm-Pre-allocate-PGD-entries-vmalloc-modules-area/20230530-020212
base: ac9a78681b921877518763ba0e89202254349d1b
patch link: https://lore.kernel.org/r/20230529180023.289904-1-bjorn%40kernel.org
patch subject: [PATCH] riscv: mm: Pre-allocate PGD entries vmalloc/modules area
config: riscv-randconfig-r042-20230530 (https://download.01.org/0day-ci/archive/20230531/202305310822.dhnyydJC-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 12.3.0
reproduce (this is a W=1 build):
mkdir -p ~/bin
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/9383adbcdfb7f850149742579615e8c174328a78
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Bj-rn-T-pel/riscv-mm-Pre-allocate-PGD-entries-vmalloc-modules-area/20230530-020212
git checkout 9383adbcdfb7f850149742579615e8c174328a78
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.3.0 ~/bin/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.3.0 ~/bin/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash arch/riscv/mm/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202305310822.dhnyydJC-lkp@intel.com/
All warnings (new ones prefixed by >>):
arch/riscv/mm/init.c: In function 'preallocate_pgd_pages_range':
arch/riscv/mm/init.c:1381:30: error: implicit declaration of function 'pgd_offset_k'; did you mean 'p4d_offset'? [-Werror=implicit-function-declaration]
1381 | pgd_t *pgd = pgd_offset_k(addr);
| ^~~~~~~~~~~~
| p4d_offset
>> arch/riscv/mm/init.c:1381:30: warning: initialization of 'pgd_t *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
arch/riscv/mm/init.c:1387:23: error: implicit declaration of function 'p4d_alloc'; did you mean 'd_alloc'? [-Werror=implicit-function-declaration]
1387 | p4d = p4d_alloc(&init_mm, pgd, addr);
| ^~~~~~~~~
| d_alloc
>> arch/riscv/mm/init.c:1387:21: warning: assignment to 'p4d_t *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
1387 | p4d = p4d_alloc(&init_mm, pgd, addr);
| ^
arch/riscv/mm/init.c:1395:23: error: implicit declaration of function 'pud_alloc'; did you mean 'd_alloc'? [-Werror=implicit-function-declaration]
1395 | pud = pud_alloc(&init_mm, p4d, addr);
| ^~~~~~~~~
| d_alloc
>> arch/riscv/mm/init.c:1395:21: warning: assignment to 'pud_t *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
1395 | pud = pud_alloc(&init_mm, p4d, addr);
| ^
arch/riscv/mm/init.c:1403:23: error: implicit declaration of function 'pmd_alloc'; did you mean 'mm_alloc'? [-Werror=implicit-function-declaration]
1403 | pmd = pmd_alloc(&init_mm, pud, addr);
| ^~~~~~~~~
| mm_alloc
>> arch/riscv/mm/init.c:1403:21: warning: assignment to 'pmd_t *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
1403 | pmd = pmd_alloc(&init_mm, pud, addr);
| ^
arch/riscv/mm/init.c: In function 'pgtable_cache_init':
arch/riscv/mm/init.c:1421:45: error: 'MODULES_VADDR' undeclared (first use in this function)
1421 | preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules");
| ^~~~~~~~~~~~~
arch/riscv/mm/init.c:1421:45: note: each undeclared identifier is reported only once for each function it appears in
arch/riscv/mm/init.c:1421:60: error: 'MODULES_END' undeclared (first use in this function)
1421 | preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules");
| ^~~~~~~~~~~
cc1: some warnings being treated as errors
vim +1381 arch/riscv/mm/init.c
1366
1367 #ifdef CONFIG_64BIT
1368 /*
1369 * Pre-allocates page-table pages for a specific area in the kernel
1370 * page-table. Only the level which needs to be synchronized between
1371 * all page-tables is allocated because the synchronization can be
1372 * expensive.
1373 */
1374 static void __init preallocate_pgd_pages_range(unsigned long start, unsigned long end,
1375 const char *area)
1376 {
1377 unsigned long addr;
1378 const char *lvl;
1379
1380 for (addr = start; addr < end && addr >= start; addr = ALIGN(addr + 1, PGDIR_SIZE)) {
> 1381 pgd_t *pgd = pgd_offset_k(addr);
1382 p4d_t *p4d;
1383 pud_t *pud;
1384 pmd_t *pmd;
1385
1386 lvl = "p4d";
> 1387 p4d = p4d_alloc(&init_mm, pgd, addr);
1388 if (!p4d)
1389 goto failed;
1390
1391 if (pgtable_l5_enabled)
1392 continue;
1393
1394 lvl = "pud";
> 1395 pud = pud_alloc(&init_mm, p4d, addr);
1396 if (!pud)
1397 goto failed;
1398
1399 if (pgtable_l4_enabled)
1400 continue;
1401
1402 lvl = "pmd";
> 1403 pmd = pmd_alloc(&init_mm, pud, addr);
1404 if (!pmd)
1405 goto failed;
1406 }
1407 return;
1408
1409 failed:
1410 /*
1411 * The pages have to be there now or they will be missing in
1412 * process page-tables later.
1413 */
1414 panic("Failed to pre-allocate %s pages for %s area\n", lvl, area);
1415 }
1416
Hi Björn,
kernel test robot noticed the following build errors:
[auto build test ERROR on ac9a78681b921877518763ba0e89202254349d1b]
url: https://github.com/intel-lab-lkp/linux/commits/Bj-rn-T-pel/riscv-mm-Pre-allocate-PGD-entries-vmalloc-modules-area/20230530-020212
base: ac9a78681b921877518763ba0e89202254349d1b
patch link: https://lore.kernel.org/r/20230529180023.289904-1-bjorn%40kernel.org
patch subject: [PATCH] riscv: mm: Pre-allocate PGD entries vmalloc/modules area
config: riscv-randconfig-r042-20230530 (https://download.01.org/0day-ci/archive/20230531/202305311117.huD9v4Y8-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 12.3.0
reproduce (this is a W=1 build):
mkdir -p ~/bin
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/9383adbcdfb7f850149742579615e8c174328a78
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Bj-rn-T-pel/riscv-mm-Pre-allocate-PGD-entries-vmalloc-modules-area/20230530-020212
git checkout 9383adbcdfb7f850149742579615e8c174328a78
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.3.0 ~/bin/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.3.0 ~/bin/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202305311117.huD9v4Y8-lkp@intel.com/
All errors (new ones prefixed by >>):
arch/riscv/mm/init.c: In function 'preallocate_pgd_pages_range':
>> arch/riscv/mm/init.c:1381:30: error: implicit declaration of function 'pgd_offset_k'; did you mean 'p4d_offset'? [-Werror=implicit-function-declaration]
1381 | pgd_t *pgd = pgd_offset_k(addr);
| ^~~~~~~~~~~~
| p4d_offset
arch/riscv/mm/init.c:1381:30: warning: initialization of 'pgd_t *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
>> arch/riscv/mm/init.c:1387:23: error: implicit declaration of function 'p4d_alloc'; did you mean 'd_alloc'? [-Werror=implicit-function-declaration]
1387 | p4d = p4d_alloc(&init_mm, pgd, addr);
| ^~~~~~~~~
| d_alloc
arch/riscv/mm/init.c:1387:21: warning: assignment to 'p4d_t *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
1387 | p4d = p4d_alloc(&init_mm, pgd, addr);
| ^
>> arch/riscv/mm/init.c:1395:23: error: implicit declaration of function 'pud_alloc'; did you mean 'd_alloc'? [-Werror=implicit-function-declaration]
1395 | pud = pud_alloc(&init_mm, p4d, addr);
| ^~~~~~~~~
| d_alloc
arch/riscv/mm/init.c:1395:21: warning: assignment to 'pud_t *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
1395 | pud = pud_alloc(&init_mm, p4d, addr);
| ^
>> arch/riscv/mm/init.c:1403:23: error: implicit declaration of function 'pmd_alloc'; did you mean 'mm_alloc'? [-Werror=implicit-function-declaration]
1403 | pmd = pmd_alloc(&init_mm, pud, addr);
| ^~~~~~~~~
| mm_alloc
arch/riscv/mm/init.c:1403:21: warning: assignment to 'pmd_t *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
1403 | pmd = pmd_alloc(&init_mm, pud, addr);
| ^
arch/riscv/mm/init.c: In function 'pgtable_cache_init':
>> arch/riscv/mm/init.c:1421:45: error: 'MODULES_VADDR' undeclared (first use in this function)
1421 | preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules");
| ^~~~~~~~~~~~~
arch/riscv/mm/init.c:1421:45: note: each undeclared identifier is reported only once for each function it appears in
>> arch/riscv/mm/init.c:1421:60: error: 'MODULES_END' undeclared (first use in this function)
1421 | preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules");
| ^~~~~~~~~~~
cc1: some warnings being treated as errors
vim +1381 arch/riscv/mm/init.c
1366
1367 #ifdef CONFIG_64BIT
1368 /*
1369 * Pre-allocates page-table pages for a specific area in the kernel
1370 * page-table. Only the level which needs to be synchronized between
1371 * all page-tables is allocated because the synchronization can be
1372 * expensive.
1373 */
1374 static void __init preallocate_pgd_pages_range(unsigned long start, unsigned long end,
1375 const char *area)
1376 {
1377 unsigned long addr;
1378 const char *lvl;
1379
1380 for (addr = start; addr < end && addr >= start; addr = ALIGN(addr + 1, PGDIR_SIZE)) {
> 1381 pgd_t *pgd = pgd_offset_k(addr);
1382 p4d_t *p4d;
1383 pud_t *pud;
1384 pmd_t *pmd;
1385
1386 lvl = "p4d";
> 1387 p4d = p4d_alloc(&init_mm, pgd, addr);
1388 if (!p4d)
1389 goto failed;
1390
1391 if (pgtable_l5_enabled)
1392 continue;
1393
1394 lvl = "pud";
> 1395 pud = pud_alloc(&init_mm, p4d, addr);
1396 if (!pud)
1397 goto failed;
1398
1399 if (pgtable_l4_enabled)
1400 continue;
1401
1402 lvl = "pmd";
> 1403 pmd = pmd_alloc(&init_mm, pud, addr);
1404 if (!pmd)
1405 goto failed;
1406 }
1407 return;
1408
1409 failed:
1410 /*
1411 * The pages have to be there now or they will be missing in
1412 * process page-tables later.
1413 */
1414 panic("Failed to pre-allocate %s pages for %s area\n", lvl, area);
1415 }
1416
1417 void __init pgtable_cache_init(void)
1418 {
1419 preallocate_pgd_pages_range(VMALLOC_START, VMALLOC_END, "vmalloc");
1420 if (IS_ENABLED(CONFIG_MODULES))
> 1421 preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules");
On Mon, 29 May 2023 11:00:23 PDT (-0700), bjorn@kernel.org wrote: > From: Björn Töpel <bjorn@rivosinc.com> > > The RISC-V port requires that kernel PGD entries are to be > synchronized between MMs. This is done via the vmalloc_fault() > function, that simply copies the PGD entries from init_mm to the > faulting one. > > Historically, faulting in PGD entries have been a source for both bugs > [1], and poor performance. > > One way to get rid of vmalloc faults is by pre-allocating the PGD > entries. Pre-allocating the entries potientially wastes 64 * 4K (65 on > SV39). The pre-allocation function is pulled from Jörg Rödel's x86 > work, with the addition of 3-level page tables (PMD allocations). > > The pmd_alloc() function needs the ptlock cache to be initialized > (when split page locks is enabled), so the pre-allocation is done in a > RISC-V specific pgtable_cache_init() implementation. > > Pre-allocate the kernel PGD entries for the vmalloc/modules area, but > only for 64b platforms. > > Link: https://lore.kernel.org/lkml/20200508144043.13893-1-joro@8bytes.org/ # [1] > Signed-off-by: Björn Töpel <bjorn@rivosinc.com> > --- > arch/riscv/mm/fault.c | 20 +++------------ > arch/riscv/mm/init.c | 58 +++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 62 insertions(+), 16 deletions(-) > > diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c > index 8685f85a7474..6b0b5e517e12 100644 > --- a/arch/riscv/mm/fault.c > +++ b/arch/riscv/mm/fault.c > @@ -230,32 +230,20 @@ void handle_page_fault(struct pt_regs *regs) > return; > > /* > - * Fault-in kernel-space virtual memory on-demand. > - * The 'reference' page table is init_mm.pgd. > + * Fault-in kernel-space virtual memory on-demand, for 32-bit > + * architectures. The 'reference' page table is init_mm.pgd. That wording seems a little odd to me: I think English allows for these "add something after the comma to change the meaning of a sentence" things, but they're kind of complicated. Maybe it's easier to just flip the order? That said, it's very early so maybe it's fine... > * > * NOTE! We MUST NOT take any locks for this case. We may > * be in an interrupt or a critical region, and should > * only copy the information from the master page table, > * nothing more. > */ > - if (unlikely((addr >= VMALLOC_START) && (addr < VMALLOC_END))) { > + if (!IS_ENABLED(CONFIG_64BIT) && > + unlikely(addr >= VMALLOC_START && addr < VMALLOC_END)) { > vmalloc_fault(regs, code, addr); > return; > } > > -#ifdef CONFIG_64BIT > - /* > - * Modules in 64bit kernels lie in their own virtual region which is not > - * in the vmalloc region, but dealing with page faults in this region > - * or the vmalloc region amounts to doing the same thing: checking that > - * the mapping exists in init_mm.pgd and updating user page table, so > - * just use vmalloc_fault. > - */ > - if (unlikely(addr >= MODULES_VADDR && addr < MODULES_END)) { > - vmalloc_fault(regs, code, addr); > - return; > - } > -#endif > /* Enable interrupts if they were enabled in the parent context. */ > if (!regs_irqs_disabled(regs)) > local_irq_enable(); > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > index 747e5b1ef02d..38bd4dd95276 100644 > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -1363,3 +1363,61 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, > return vmemmap_populate_basepages(start, end, node, NULL); > } > #endif > + > +#ifdef CONFIG_64BIT > +/* > + * Pre-allocates page-table pages for a specific area in the kernel > + * page-table. Only the level which needs to be synchronized between > + * all page-tables is allocated because the synchronization can be > + * expensive. > + */ > +static void __init preallocate_pgd_pages_range(unsigned long start, unsigned long end, > + const char *area) > +{ > + unsigned long addr; > + const char *lvl; > + > + for (addr = start; addr < end && addr >= start; addr = ALIGN(addr + 1, PGDIR_SIZE)) { > + pgd_t *pgd = pgd_offset_k(addr); > + p4d_t *p4d; > + pud_t *pud; > + pmd_t *pmd; > + > + lvl = "p4d"; > + p4d = p4d_alloc(&init_mm, pgd, addr); > + if (!p4d) > + goto failed; > + > + if (pgtable_l5_enabled) > + continue; > + > + lvl = "pud"; > + pud = pud_alloc(&init_mm, p4d, addr); > + if (!pud) > + goto failed; > + > + if (pgtable_l4_enabled) > + continue; > + > + lvl = "pmd"; > + pmd = pmd_alloc(&init_mm, pud, addr); > + if (!pmd) > + goto failed; > + } > + return; > + > +failed: > + /* > + * The pages have to be there now or they will be missing in > + * process page-tables later. > + */ > + panic("Failed to pre-allocate %s pages for %s area\n", lvl, area); > +} > + > +void __init pgtable_cache_init(void) > +{ > + preallocate_pgd_pages_range(VMALLOC_START, VMALLOC_END, "vmalloc"); > + if (IS_ENABLED(CONFIG_MODULES)) > + preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules"); > +} > +#endif > > base-commit: ac9a78681b921877518763ba0e89202254349d1b Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> aside from the build issue, which seems pretty straight-forward. I'm going to drop this from patchwork.
Palmer Dabbelt <palmer@dabbelt.com> writes: > On Mon, 29 May 2023 11:00:23 PDT (-0700), bjorn@kernel.org wrote: >> From: Björn Töpel <bjorn@rivosinc.com> >> >> The RISC-V port requires that kernel PGD entries are to be >> synchronized between MMs. This is done via the vmalloc_fault() >> function, that simply copies the PGD entries from init_mm to the >> faulting one. >> >> Historically, faulting in PGD entries have been a source for both bugs >> [1], and poor performance. >> >> One way to get rid of vmalloc faults is by pre-allocating the PGD >> entries. Pre-allocating the entries potientially wastes 64 * 4K (65 on >> SV39). The pre-allocation function is pulled from Jörg Rödel's x86 >> work, with the addition of 3-level page tables (PMD allocations). >> >> The pmd_alloc() function needs the ptlock cache to be initialized >> (when split page locks is enabled), so the pre-allocation is done in a >> RISC-V specific pgtable_cache_init() implementation. >> >> Pre-allocate the kernel PGD entries for the vmalloc/modules area, but >> only for 64b platforms. >> >> Link: https://lore.kernel.org/lkml/20200508144043.13893-1-joro@8bytes.org/ # [1] >> Signed-off-by: Björn Töpel <bjorn@rivosinc.com> >> --- >> arch/riscv/mm/fault.c | 20 +++------------ >> arch/riscv/mm/init.c | 58 +++++++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 62 insertions(+), 16 deletions(-) >> >> diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c >> index 8685f85a7474..6b0b5e517e12 100644 >> --- a/arch/riscv/mm/fault.c >> +++ b/arch/riscv/mm/fault.c >> @@ -230,32 +230,20 @@ void handle_page_fault(struct pt_regs *regs) >> return; >> >> /* >> - * Fault-in kernel-space virtual memory on-demand. >> - * The 'reference' page table is init_mm.pgd. >> + * Fault-in kernel-space virtual memory on-demand, for 32-bit >> + * architectures. The 'reference' page table is init_mm.pgd. > > That wording seems a little odd to me: I think English allows for these > "add something after the comma to change the meaning of a sentence" > things, but they're kind of complicated. Maybe it's easier to just flip > the order? > > That said, it's very early so maybe it's fine... > >> * >> * NOTE! We MUST NOT take any locks for this case. We may >> * be in an interrupt or a critical region, and should >> * only copy the information from the master page table, >> * nothing more. >> */ >> - if (unlikely((addr >= VMALLOC_START) && (addr < VMALLOC_END))) { >> + if (!IS_ENABLED(CONFIG_64BIT) && >> + unlikely(addr >= VMALLOC_START && addr < VMALLOC_END)) { >> vmalloc_fault(regs, code, addr); >> return; >> } >> >> -#ifdef CONFIG_64BIT >> - /* >> - * Modules in 64bit kernels lie in their own virtual region which is not >> - * in the vmalloc region, but dealing with page faults in this region >> - * or the vmalloc region amounts to doing the same thing: checking that >> - * the mapping exists in init_mm.pgd and updating user page table, so >> - * just use vmalloc_fault. >> - */ >> - if (unlikely(addr >= MODULES_VADDR && addr < MODULES_END)) { >> - vmalloc_fault(regs, code, addr); >> - return; >> - } >> -#endif >> /* Enable interrupts if they were enabled in the parent context. */ >> if (!regs_irqs_disabled(regs)) >> local_irq_enable(); >> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c >> index 747e5b1ef02d..38bd4dd95276 100644 >> --- a/arch/riscv/mm/init.c >> +++ b/arch/riscv/mm/init.c >> @@ -1363,3 +1363,61 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, >> return vmemmap_populate_basepages(start, end, node, NULL); >> } >> #endif >> + >> +#ifdef CONFIG_64BIT >> +/* >> + * Pre-allocates page-table pages for a specific area in the kernel >> + * page-table. Only the level which needs to be synchronized between >> + * all page-tables is allocated because the synchronization can be >> + * expensive. >> + */ >> +static void __init preallocate_pgd_pages_range(unsigned long start, unsigned long end, >> + const char *area) >> +{ >> + unsigned long addr; >> + const char *lvl; >> + >> + for (addr = start; addr < end && addr >= start; addr = ALIGN(addr + 1, PGDIR_SIZE)) { >> + pgd_t *pgd = pgd_offset_k(addr); >> + p4d_t *p4d; >> + pud_t *pud; >> + pmd_t *pmd; >> + >> + lvl = "p4d"; >> + p4d = p4d_alloc(&init_mm, pgd, addr); >> + if (!p4d) >> + goto failed; >> + >> + if (pgtable_l5_enabled) >> + continue; >> + >> + lvl = "pud"; >> + pud = pud_alloc(&init_mm, p4d, addr); >> + if (!pud) >> + goto failed; >> + >> + if (pgtable_l4_enabled) >> + continue; >> + >> + lvl = "pmd"; >> + pmd = pmd_alloc(&init_mm, pud, addr); >> + if (!pmd) >> + goto failed; >> + } >> + return; >> + >> +failed: >> + /* >> + * The pages have to be there now or they will be missing in >> + * process page-tables later. >> + */ >> + panic("Failed to pre-allocate %s pages for %s area\n", lvl, area); >> +} >> + >> +void __init pgtable_cache_init(void) >> +{ >> + preallocate_pgd_pages_range(VMALLOC_START, VMALLOC_END, "vmalloc"); >> + if (IS_ENABLED(CONFIG_MODULES)) >> + preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules"); >> +} >> +#endif >> >> base-commit: ac9a78681b921877518763ba0e89202254349d1b > > Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> > > aside from the build issue, which seems pretty straight-forward. I'm > going to drop this from patchwork. Hmm, you applied the V2 a couple of days ago [1], which fixes the build issue. Did you drop the V2 from the queue? [1] https://lore.kernel.org/linux-riscv/168727442024.569.16572247474971535604.git-patchwork-notify@kernel.org/ Björn
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index 8685f85a7474..6b0b5e517e12 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -230,32 +230,20 @@ void handle_page_fault(struct pt_regs *regs) return; /* - * Fault-in kernel-space virtual memory on-demand. - * The 'reference' page table is init_mm.pgd. + * Fault-in kernel-space virtual memory on-demand, for 32-bit + * architectures. The 'reference' page table is init_mm.pgd. * * NOTE! We MUST NOT take any locks for this case. We may * be in an interrupt or a critical region, and should * only copy the information from the master page table, * nothing more. */ - if (unlikely((addr >= VMALLOC_START) && (addr < VMALLOC_END))) { + if (!IS_ENABLED(CONFIG_64BIT) && + unlikely(addr >= VMALLOC_START && addr < VMALLOC_END)) { vmalloc_fault(regs, code, addr); return; } -#ifdef CONFIG_64BIT - /* - * Modules in 64bit kernels lie in their own virtual region which is not - * in the vmalloc region, but dealing with page faults in this region - * or the vmalloc region amounts to doing the same thing: checking that - * the mapping exists in init_mm.pgd and updating user page table, so - * just use vmalloc_fault. - */ - if (unlikely(addr >= MODULES_VADDR && addr < MODULES_END)) { - vmalloc_fault(regs, code, addr); - return; - } -#endif /* Enable interrupts if they were enabled in the parent context. */ if (!regs_irqs_disabled(regs)) local_irq_enable(); diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 747e5b1ef02d..38bd4dd95276 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -1363,3 +1363,61 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, return vmemmap_populate_basepages(start, end, node, NULL); } #endif + +#ifdef CONFIG_64BIT +/* + * Pre-allocates page-table pages for a specific area in the kernel + * page-table. Only the level which needs to be synchronized between + * all page-tables is allocated because the synchronization can be + * expensive. + */ +static void __init preallocate_pgd_pages_range(unsigned long start, unsigned long end, + const char *area) +{ + unsigned long addr; + const char *lvl; + + for (addr = start; addr < end && addr >= start; addr = ALIGN(addr + 1, PGDIR_SIZE)) { + pgd_t *pgd = pgd_offset_k(addr); + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + + lvl = "p4d"; + p4d = p4d_alloc(&init_mm, pgd, addr); + if (!p4d) + goto failed; + + if (pgtable_l5_enabled) + continue; + + lvl = "pud"; + pud = pud_alloc(&init_mm, p4d, addr); + if (!pud) + goto failed; + + if (pgtable_l4_enabled) + continue; + + lvl = "pmd"; + pmd = pmd_alloc(&init_mm, pud, addr); + if (!pmd) + goto failed; + } + return; + +failed: + /* + * The pages have to be there now or they will be missing in + * process page-tables later. + */ + panic("Failed to pre-allocate %s pages for %s area\n", lvl, area); +} + +void __init pgtable_cache_init(void) +{ + preallocate_pgd_pages_range(VMALLOC_START, VMALLOC_END, "vmalloc"); + if (IS_ENABLED(CONFIG_MODULES)) + preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules"); +} +#endif