| Message ID | 20200709091054.1698-3-yezhenyu2@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: tlb: add support for TLBI RANGE instructions | expand |
On 2020/7/9 17:10, Zhenyu Ye wrote: > + /* > + * When cpu does not support TLBI RANGE feature, we flush the tlb > + * entries one by one at the granularity of 'stride'. > + * When cpu supports the TLBI RANGE feature, then: > + * 1. If pages is odd, flush the first page through non-RANGE > + * instruction; > + * 2. For remaining pages: The minimum range granularity is decided > + * by 'scale', so we can not flush all pages by one instruction > + * in some cases. > + * > + * For example, when the pages = 0xe81a, let's start 'scale' from > + * maximum, and find right 'num' for each 'scale': > + * > + * When scale = 3, we can flush no pages because the minumum > + * range is 2^(5*3 + 1) = 0x10000. > + * When scale = 2, the minimum range is 2^(5*2 + 1) = 0x800, we can > + * flush 0xe800 pages this time, the num = 0xe800/0x800 - 1 = 0x1c. > + * Remain pages is 0x1a; > + * When scale = 1, the minimum range is 2^(5*1 + 1) = 0x40, no page > + * can be flushed. > + * When scale = 0, we flush the remaining 0x1a pages, the num = > + * 0x1a/0x2 - 1 = 0xd. > + * > + * However, in most scenarios, the pages = 1 when flush_tlb_range() is > + * called. Start from scale = 3 or other proper value (such as scale = > + * ilog2(pages)), will incur extra overhead. > + * So increase 'scale' from 0 to maximum, the flush order is exactly > + * opposite to the example. > + */ The comments may be too long, probably should be moved to commit messages. Thanks, Zhenyu
On Thu, Jul 09, 2020 at 05:10:54PM +0800, Zhenyu Ye wrote: > Add __TLBI_VADDR_RANGE macro and rewrite __flush_tlb_range(). > > Signed-off-by: Zhenyu Ye <yezhenyu2@huawei.com> > --- > arch/arm64/include/asm/tlbflush.h | 156 ++++++++++++++++++++++++------ > 1 file changed, 126 insertions(+), 30 deletions(-) > > diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h > index 39aed2efd21b..30e52eae973b 100644 > --- a/arch/arm64/include/asm/tlbflush.h > +++ b/arch/arm64/include/asm/tlbflush.h > @@ -60,6 +60,31 @@ > __ta; \ > }) > > +/* > + * Get translation granule of the system, which is decided by > + * PAGE_SIZE. Used by TTL. > + * - 4KB : 1 > + * - 16KB : 2 > + * - 64KB : 3 > + */ > +#define TLBI_TTL_TG_4K 1 > +#define TLBI_TTL_TG_16K 2 > +#define TLBI_TTL_TG_64K 3 > + > +static inline unsigned long get_trans_granule(void) > +{ > + switch (PAGE_SIZE) { > + case SZ_4K: > + return TLBI_TTL_TG_4K; > + case SZ_16K: > + return TLBI_TTL_TG_16K; > + case SZ_64K: > + return TLBI_TTL_TG_64K; > + default: > + return 0; > + } > +} > + > /* > * Level-based TLBI operations. > * > @@ -73,29 +98,15 @@ > * in asm/stage2_pgtable.h. > */ > #define TLBI_TTL_MASK GENMASK_ULL(47, 44) > -#define TLBI_TTL_TG_4K 1 > -#define TLBI_TTL_TG_16K 2 > -#define TLBI_TTL_TG_64K 3 > > #define __tlbi_level(op, addr, level) do { \ > u64 arg = addr; \ > \ > if (cpus_have_const_cap(ARM64_HAS_ARMv8_4_TTL) && \ > + !cpus_have_const_cap(ARM64_HAS_TLBI_RANGE) && \ > level) { \ > u64 ttl = level & 3; \ > - \ > - switch (PAGE_SIZE) { \ > - case SZ_4K: \ > - ttl |= TLBI_TTL_TG_4K << 2; \ > - break; \ > - case SZ_16K: \ > - ttl |= TLBI_TTL_TG_16K << 2; \ > - break; \ > - case SZ_64K: \ > - ttl |= TLBI_TTL_TG_64K << 2; \ > - break; \ > - } \ > - \ > + ttl |= get_trans_granule() << 2; \ > arg &= ~TLBI_TTL_MASK; \ > arg |= FIELD_PREP(TLBI_TTL_MASK, ttl); \ > } \ I think checking for !ARM64_HAS_TLBI_RANGE here is incorrect. I can see why you attempted this since the range and classic ops have a different position for the level but now you are not passing the TTL at all for the classic TLBI. It's also inconsistent to have the range ops get the level in the addr argument while the classic ops added in the __tlbi_level macro. I'd rather have two sets of macros, __tlbi_level and __tlbi_range_level, called depending on whether you use classic or range ops. > @@ -108,6 +119,49 @@ > __tlbi_level(op, (arg | USER_ASID_FLAG), level); \ > } while (0) > > +#define __tlbi_last_level(op1, op2, arg, last_level, tlb_level) do { \ > + if (last_level) { \ > + __tlbi_level(op1, arg, tlb_level); \ > + __tlbi_user_level(op1, arg, tlb_level); \ > + } else { \ > + __tlbi_level(op2, arg, tlb_level); \ > + __tlbi_user_level(op2, arg, tlb_level); \ > + } \ > +} while (0) And you could drop this altogether. I know it's slightly more lines of code but keeping it expanded in __flush_tlb_range() would be clearer. > + > +/* > + * This macro creates a properly formatted VA operand for the TLBI RANGE. > + * The value bit assignments are: > + * > + * +----------+------+-------+-------+-------+----------------------+ > + * | ASID | TG | SCALE | NUM | TTL | BADDR | > + * +-----------------+-------+-------+-------+----------------------+ > + * |63 48|47 46|45 44|43 39|38 37|36 0| > + * > + * The address range is determined by below formula: > + * [BADDR, BADDR + (NUM + 1) * 2^(5*SCALE + 1) * PAGESIZE) > + * > + */ > +#define __TLBI_VADDR_RANGE(addr, asid, scale, num, ttl) \ > + ({ \ > + unsigned long __ta = (addr) >> PAGE_SHIFT; \ > + __ta &= GENMASK_ULL(36, 0); \ > + __ta |= (unsigned long)(ttl) << 37; \ > + __ta |= (unsigned long)(num) << 39; \ > + __ta |= (unsigned long)(scale) << 44; \ > + __ta |= get_trans_granule() << 46; \ > + __ta |= (unsigned long)(asid) << 48; \ > + __ta; \ > + }) As per above, I'd remove the ttl here and just add it in the __tlbi_level_range(). For consistency, you could do the same with num and scale, just leave the asid and addr, similar to __TLBI_VADDR (the only difference is the shift by PAGE_SHIFT rather than 12). > + > +/* These macros are used by the TLBI RANGE feature. */ > +#define __TLBI_RANGE_PAGES(num, scale) (((num) + 1) << (5 * (scale) + 1)) > +#define MAX_TLBI_RANGE_PAGES __TLBI_RANGE_PAGES(31, 3) > + > +#define TLBI_RANGE_MASK GENMASK_ULL(4, 0) > +#define __TLBI_RANGE_NUM(range, scale) \ > + (((range) >> (5 * (scale) + 1)) & TLBI_RANGE_MASK) > + > /* > * TLB Invalidation > * ================ > @@ -232,32 +286,74 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma, > unsigned long stride, bool last_level, > int tlb_level) > { > + int num = 0; > + int scale = 0; > unsigned long asid = ASID(vma->vm_mm); > unsigned long addr; > + unsigned long pages; > > start = round_down(start, stride); > end = round_up(end, stride); > + pages = (end - start) >> PAGE_SHIFT; > > - if ((end - start) >= (MAX_TLBI_OPS * stride)) { > + if ((!cpus_have_const_cap(ARM64_HAS_TLBI_RANGE) && > + (end - start) >= (MAX_TLBI_OPS * stride)) || > + pages >= MAX_TLBI_RANGE_PAGES) { > flush_tlb_mm(vma->vm_mm); > return; > } > > - /* Convert the stride into units of 4k */ > - stride >>= 12; > - > - start = __TLBI_VADDR(start, asid); > - end = __TLBI_VADDR(end, asid); > - > dsb(ishst); > - for (addr = start; addr < end; addr += stride) { > - if (last_level) { > - __tlbi_level(vale1is, addr, tlb_level); > - __tlbi_user_level(vale1is, addr, tlb_level); > - } else { > - __tlbi_level(vae1is, addr, tlb_level); > - __tlbi_user_level(vae1is, addr, tlb_level); > + > + /* > + * When cpu does not support TLBI RANGE feature, we flush the tlb > + * entries one by one at the granularity of 'stride'. > + * When cpu supports the TLBI RANGE feature, then: > + * 1. If pages is odd, flush the first page through non-RANGE > + * instruction; > + * 2. For remaining pages: The minimum range granularity is decided > + * by 'scale', so we can not flush all pages by one instruction > + * in some cases. This part can stay in the code. In addition, you could mention something along the lines that it starts from scale 0 (covering num * 2 pages) and increments it until no pages left. > + * > + * For example, when the pages = 0xe81a, let's start 'scale' from > + * maximum, and find right 'num' for each 'scale': > + * > + * When scale = 3, we can flush no pages because the minumum > + * range is 2^(5*3 + 1) = 0x10000. > + * When scale = 2, the minimum range is 2^(5*2 + 1) = 0x800, we can > + * flush 0xe800 pages this time, the num = 0xe800/0x800 - 1 = 0x1c. > + * Remain pages is 0x1a; > + * When scale = 1, the minimum range is 2^(5*1 + 1) = 0x40, no page > + * can be flushed. > + * When scale = 0, we flush the remaining 0x1a pages, the num = > + * 0x1a/0x2 - 1 = 0xd. > + * > + * However, in most scenarios, the pages = 1 when flush_tlb_range() is > + * called. Start from scale = 3 or other proper value (such as scale = > + * ilog2(pages)), will incur extra overhead. > + * So increase 'scale' from 0 to maximum, the flush order is exactly > + * opposite to the example. > + */ I'd drop the example from the code, just move it to the commit log. > + while (pages > 0) { > + if (cpus_have_const_cap(ARM64_HAS_TLBI_RANGE) && > + pages % 2 == 0) { > + num = __TLBI_RANGE_NUM(pages, scale) - 1; > + if (num >= 0) { > + addr = __TLBI_VADDR_RANGE(start, asid, scale, > + num, tlb_level); > + __tlbi_last_level(rvale1is, rvae1is, addr, > + last_level, tlb_level); > + start += __TLBI_RANGE_PAGES(num, scale) << PAGE_SHIFT; > + pages -= __TLBI_RANGE_PAGES(num, scale); > + } > + scale++; > + continue; > } > + > + addr = __TLBI_VADDR(start, asid); > + __tlbi_last_level(vale1is, vae1is, addr, last_level, tlb_level); > + start += stride; > + pages -= stride >> PAGE_SHIFT; > } > dsb(ish); As I mentioned above, just keep the "if (last_level)" expanded here in both cases. Maybe you could place a "pages % 2 == 1" check first to avoid the indentation. Something like: while (pages > 0) { if (!cpus_have_const_cap(ARM64_HAS_TLBI_RANGE) || pages % 2 == 1) { ... __tlbi_level(); ... continue; } num = __TLBI_RANGE_NUM(pages, scale) - 1; if (num >= 0) { ... } scale++; continue; } Thanks.
Hi Catalin, On 2020/7/10 1:36, Catalin Marinas wrote: > On Thu, Jul 09, 2020 at 05:10:54PM +0800, Zhenyu Ye wrote: >> #define __tlbi_level(op, addr, level) do { \ >> u64 arg = addr; \ >> \ >> if (cpus_have_const_cap(ARM64_HAS_ARMv8_4_TTL) && \ >> + !cpus_have_const_cap(ARM64_HAS_TLBI_RANGE) && \ >> level) { \ >> u64 ttl = level & 3; \ >> - \ >> - switch (PAGE_SIZE) { \ >> - case SZ_4K: \ >> - ttl |= TLBI_TTL_TG_4K << 2; \ >> - break; \ >> - case SZ_16K: \ >> - ttl |= TLBI_TTL_TG_16K << 2; \ >> - break; \ >> - case SZ_64K: \ >> - ttl |= TLBI_TTL_TG_64K << 2; \ >> - break; \ >> - } \ >> - \ >> + ttl |= get_trans_granule() << 2; \ >> arg &= ~TLBI_TTL_MASK; \ >> arg |= FIELD_PREP(TLBI_TTL_MASK, ttl); \ >> } \ > > I think checking for !ARM64_HAS_TLBI_RANGE here is incorrect. I can see > why you attempted this since the range and classic ops have a different > position for the level but now you are not passing the TTL at all for > the classic TLBI. It's also inconsistent to have the range ops get the > level in the addr argument while the classic ops added in the > __tlbi_level macro. > You are right, this is really a serious problem. But this can be avoided after removing the check for ARM64_HAS_TLBI_RANGE and dropping the __tlbi_last_level. Just call __tlbi() and __tlbi_user() when doing range ops. > I'd rather have two sets of macros, __tlbi_level and __tlbi_range_level, > called depending on whether you use classic or range ops. > Then we have to add __tlbi_user_range_level, too. And if we move the num and scale out of __TLBI_VADDR_RANGE, the __TLBI_VADDR_RANGE macro will make little sense (addr and asid also can be moved out). __TLBI_VADDR macro is defined to create a properly formatted VA operand for the TLBI, then how about add the level to __TLBI_VADDR, just like: #define __TLBI_VADDR(addr, asid, level) \ ({ \ unsigned long __ta = (addr) >> 12; \ __ta &= GENMASK_ULL(43, 0); \ __ta |= (unsigned long)(asid) << 48; \ if (cpus_have_const_cap(ARM64_HAS_ARMv8_4_TTL)) { \ u64 ttl = get_trans_granule() << 2 + level & 3; \ __ta |= ttl << 44; \ } \ __ta; \ }) Then we should make sure __TLBI_VADDR is used for all TLBI operands. But the related code has changed a lot in this merge window, so I perfer to do this in the future, after all below be merged: git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git kvm-arm64/el2-obj-v4.1 git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git kvm-arm64/pre-nv-5.9 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/tlbi Currently, keep the range ops get the level in the addr argument, the classic ops added the level in the __tlbi_level macro. >> @@ -108,6 +119,49 @@ >> __tlbi_level(op, (arg | USER_ASID_FLAG), level); \ >> } while (0) >> >> +#define __tlbi_last_level(op1, op2, arg, last_level, tlb_level) do { \ >> + if (last_level) { \ >> + __tlbi_level(op1, arg, tlb_level); \ >> + __tlbi_user_level(op1, arg, tlb_level); \ >> + } else { \ >> + __tlbi_level(op2, arg, tlb_level); \ >> + __tlbi_user_level(op2, arg, tlb_level); \ >> + } \ >> +} while (0) > > And you could drop this altogether. I know it's slightly more lines of > code but keeping it expanded in __flush_tlb_range() would be clearer. Thanks, Zhenyu
diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h index 39aed2efd21b..30e52eae973b 100644 --- a/arch/arm64/include/asm/tlbflush.h +++ b/arch/arm64/include/asm/tlbflush.h @@ -60,6 +60,31 @@ __ta; \ }) +/* + * Get translation granule of the system, which is decided by + * PAGE_SIZE. Used by TTL. + * - 4KB : 1 + * - 16KB : 2 + * - 64KB : 3 + */ +#define TLBI_TTL_TG_4K 1 +#define TLBI_TTL_TG_16K 2 +#define TLBI_TTL_TG_64K 3 + +static inline unsigned long get_trans_granule(void) +{ + switch (PAGE_SIZE) { + case SZ_4K: + return TLBI_TTL_TG_4K; + case SZ_16K: + return TLBI_TTL_TG_16K; + case SZ_64K: + return TLBI_TTL_TG_64K; + default: + return 0; + } +} + /* * Level-based TLBI operations. * @@ -73,29 +98,15 @@ * in asm/stage2_pgtable.h. */ #define TLBI_TTL_MASK GENMASK_ULL(47, 44) -#define TLBI_TTL_TG_4K 1 -#define TLBI_TTL_TG_16K 2 -#define TLBI_TTL_TG_64K 3 #define __tlbi_level(op, addr, level) do { \ u64 arg = addr; \ \ if (cpus_have_const_cap(ARM64_HAS_ARMv8_4_TTL) && \ + !cpus_have_const_cap(ARM64_HAS_TLBI_RANGE) && \ level) { \ u64 ttl = level & 3; \ - \ - switch (PAGE_SIZE) { \ - case SZ_4K: \ - ttl |= TLBI_TTL_TG_4K << 2; \ - break; \ - case SZ_16K: \ - ttl |= TLBI_TTL_TG_16K << 2; \ - break; \ - case SZ_64K: \ - ttl |= TLBI_TTL_TG_64K << 2; \ - break; \ - } \ - \ + ttl |= get_trans_granule() << 2; \ arg &= ~TLBI_TTL_MASK; \ arg |= FIELD_PREP(TLBI_TTL_MASK, ttl); \ } \ @@ -108,6 +119,49 @@ __tlbi_level(op, (arg | USER_ASID_FLAG), level); \ } while (0) +#define __tlbi_last_level(op1, op2, arg, last_level, tlb_level) do { \ + if (last_level) { \ + __tlbi_level(op1, arg, tlb_level); \ + __tlbi_user_level(op1, arg, tlb_level); \ + } else { \ + __tlbi_level(op2, arg, tlb_level); \ + __tlbi_user_level(op2, arg, tlb_level); \ + } \ +} while (0) + +/* + * This macro creates a properly formatted VA operand for the TLBI RANGE. + * The value bit assignments are: + * + * +----------+------+-------+-------+-------+----------------------+ + * | ASID | TG | SCALE | NUM | TTL | BADDR | + * +-----------------+-------+-------+-------+----------------------+ + * |63 48|47 46|45 44|43 39|38 37|36 0| + * + * The address range is determined by below formula: + * [BADDR, BADDR + (NUM + 1) * 2^(5*SCALE + 1) * PAGESIZE) + * + */ +#define __TLBI_VADDR_RANGE(addr, asid, scale, num, ttl) \ + ({ \ + unsigned long __ta = (addr) >> PAGE_SHIFT; \ + __ta &= GENMASK_ULL(36, 0); \ + __ta |= (unsigned long)(ttl) << 37; \ + __ta |= (unsigned long)(num) << 39; \ + __ta |= (unsigned long)(scale) << 44; \ + __ta |= get_trans_granule() << 46; \ + __ta |= (unsigned long)(asid) << 48; \ + __ta; \ + }) + +/* These macros are used by the TLBI RANGE feature. */ +#define __TLBI_RANGE_PAGES(num, scale) (((num) + 1) << (5 * (scale) + 1)) +#define MAX_TLBI_RANGE_PAGES __TLBI_RANGE_PAGES(31, 3) + +#define TLBI_RANGE_MASK GENMASK_ULL(4, 0) +#define __TLBI_RANGE_NUM(range, scale) \ + (((range) >> (5 * (scale) + 1)) & TLBI_RANGE_MASK) + /* * TLB Invalidation * ================ @@ -232,32 +286,74 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma, unsigned long stride, bool last_level, int tlb_level) { + int num = 0; + int scale = 0; unsigned long asid = ASID(vma->vm_mm); unsigned long addr; + unsigned long pages; start = round_down(start, stride); end = round_up(end, stride); + pages = (end - start) >> PAGE_SHIFT; - if ((end - start) >= (MAX_TLBI_OPS * stride)) { + if ((!cpus_have_const_cap(ARM64_HAS_TLBI_RANGE) && + (end - start) >= (MAX_TLBI_OPS * stride)) || + pages >= MAX_TLBI_RANGE_PAGES) { flush_tlb_mm(vma->vm_mm); return; } - /* Convert the stride into units of 4k */ - stride >>= 12; - - start = __TLBI_VADDR(start, asid); - end = __TLBI_VADDR(end, asid); - dsb(ishst); - for (addr = start; addr < end; addr += stride) { - if (last_level) { - __tlbi_level(vale1is, addr, tlb_level); - __tlbi_user_level(vale1is, addr, tlb_level); - } else { - __tlbi_level(vae1is, addr, tlb_level); - __tlbi_user_level(vae1is, addr, tlb_level); + + /* + * When cpu does not support TLBI RANGE feature, we flush the tlb + * entries one by one at the granularity of 'stride'. + * When cpu supports the TLBI RANGE feature, then: + * 1. If pages is odd, flush the first page through non-RANGE + * instruction; + * 2. For remaining pages: The minimum range granularity is decided + * by 'scale', so we can not flush all pages by one instruction + * in some cases. + * + * For example, when the pages = 0xe81a, let's start 'scale' from + * maximum, and find right 'num' for each 'scale': + * + * When scale = 3, we can flush no pages because the minumum + * range is 2^(5*3 + 1) = 0x10000. + * When scale = 2, the minimum range is 2^(5*2 + 1) = 0x800, we can + * flush 0xe800 pages this time, the num = 0xe800/0x800 - 1 = 0x1c. + * Remain pages is 0x1a; + * When scale = 1, the minimum range is 2^(5*1 + 1) = 0x40, no page + * can be flushed. + * When scale = 0, we flush the remaining 0x1a pages, the num = + * 0x1a/0x2 - 1 = 0xd. + * + * However, in most scenarios, the pages = 1 when flush_tlb_range() is + * called. Start from scale = 3 or other proper value (such as scale = + * ilog2(pages)), will incur extra overhead. + * So increase 'scale' from 0 to maximum, the flush order is exactly + * opposite to the example. + */ + while (pages > 0) { + if (cpus_have_const_cap(ARM64_HAS_TLBI_RANGE) && + pages % 2 == 0) { + num = __TLBI_RANGE_NUM(pages, scale) - 1; + if (num >= 0) { + addr = __TLBI_VADDR_RANGE(start, asid, scale, + num, tlb_level); + __tlbi_last_level(rvale1is, rvae1is, addr, + last_level, tlb_level); + start += __TLBI_RANGE_PAGES(num, scale) << PAGE_SHIFT; + pages -= __TLBI_RANGE_PAGES(num, scale); + } + scale++; + continue; } + + addr = __TLBI_VADDR(start, asid); + __tlbi_last_level(vale1is, vae1is, addr, last_level, tlb_level); + start += stride; + pages -= stride >> PAGE_SHIFT; } dsb(ish); }
Add __TLBI_VADDR_RANGE macro and rewrite __flush_tlb_range(). Signed-off-by: Zhenyu Ye <yezhenyu2@huawei.com> --- arch/arm64/include/asm/tlbflush.h | 156 ++++++++++++++++++++++++------ 1 file changed, 126 insertions(+), 30 deletions(-)