[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v9 03/15] xen/bitops: implement fls{l}() in common logic
To avoid the compilation error below, it is needed to update to places in common/page_alloc.c where flsl() is used as now flsl() returns unsigned int: ./include/xen/kernel.h:18:21: error: comparison of distinct pointer types lacks a cast [-Werror] 18 | (void) (&_x == &_y); \ | ^~ common/page_alloc.c:1843:34: note: in expansion of macro 'min' 1843 | unsigned int inc_order = min(MAX_ORDER, flsl(e - s) - 1); generic_fls{l} was used instead of __builtin_clz{l}(x) as if x is 0, the result in undefined. Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx> --- The patch is almost independent from Andrew's patch series ( https://lore.kernel.org/xen-devel/20240313172716.2325427-1-andrew.cooper3@xxxxxxxxxx/T/#t) except test_fls() function which IMO can be merged as a separate patch after Andrew's patch will be fully ready. --- Changes in V9: - update return type of fls and flsl() to unsigned int to be aligned with other bit ops. - update places where return value of fls() and flsl() is compared with int. - update the commit message. --- Changes in V8: - do proper rebase: back definition of fls{l} to the current patch. - drop the changes which removed ffz() in PPC. it should be done not in this patch. - add a message after Signed-off. --- Changes in V7: - Code style fixes --- Changes in V6: - new patch for the patch series. --- xen/arch/arm/include/asm/arm32/bitops.h | 2 +- xen/arch/arm/include/asm/arm64/bitops.h | 6 ++---- xen/arch/arm/include/asm/bitops.h | 7 ++----- xen/arch/ppc/include/asm/bitops.h | 3 --- xen/arch/x86/include/asm/bitops.h | 6 ++++-- xen/common/bitops.c | 22 ++++++++++++++++++++++ xen/common/page_alloc.c | 4 ++-- xen/include/xen/bitops.h | 24 ++++++++++++++++++++++++ 8 files changed, 57 insertions(+), 17 deletions(-) diff --git a/xen/arch/arm/include/asm/arm32/bitops.h b/xen/arch/arm/include/asm/arm32/bitops.h index d0309d47c1..5552d4e945 100644 --- a/xen/arch/arm/include/asm/arm32/bitops.h +++ b/xen/arch/arm/include/asm/arm32/bitops.h @@ -1,7 +1,7 @@ #ifndef _ARM_ARM32_BITOPS_H #define _ARM_ARM32_BITOPS_H -#define flsl fls +#define arch_flsl fls /* * Little endian assembly bitops. nr = 0 -> byte 0 bit 0. diff --git a/xen/arch/arm/include/asm/arm64/bitops.h b/xen/arch/arm/include/asm/arm64/bitops.h index 0efde29068..5f5d97faa0 100644 --- a/xen/arch/arm/include/asm/arm64/bitops.h +++ b/xen/arch/arm/include/asm/arm64/bitops.h @@ -22,17 +22,15 @@ static /*__*/always_inline unsigned long __ffs(unsigned long word) */ #define ffz(x) __ffs(~(x)) -static inline int flsl(unsigned long x) +static inline int arch_flsl(unsigned long x) { uint64_t ret; - if (__builtin_constant_p(x)) - return generic_flsl(x); - asm("clz\t%0, %1" : "=r" (ret) : "r" (x)); return BITS_PER_LONG - ret; } +#define arch_flsl arch_flsl /* Based on linux/include/asm-generic/bitops/find.h */ diff --git a/xen/arch/arm/include/asm/bitops.h b/xen/arch/arm/include/asm/bitops.h index 8e16335e76..860d6d4689 100644 --- a/xen/arch/arm/include/asm/bitops.h +++ b/xen/arch/arm/include/asm/bitops.h @@ -78,17 +78,14 @@ bool clear_mask16_timeout(uint16_t mask, volatile void *p, * the clz instruction for much better code efficiency. */ -static inline int fls(unsigned int x) +static inline int arch_fls(unsigned int x) { int ret; - if (__builtin_constant_p(x)) - return generic_fls(x); - asm("clz\t%"__OP32"0, %"__OP32"1" : "=r" (ret) : "r" (x)); return 32 - ret; } - +#define arch_fls arch_fls #define arch_ffs(x) ({ unsigned int __t = (x); fls(ISOLATE_LSB(__t)); }) #define arch_ffsl(x) ({ unsigned long __t = (x); flsl(ISOLATE_LSB(__t)); }) diff --git a/xen/arch/ppc/include/asm/bitops.h b/xen/arch/ppc/include/asm/bitops.h index e2b6473c8c..ca308fd62b 100644 --- a/xen/arch/ppc/include/asm/bitops.h +++ b/xen/arch/ppc/include/asm/bitops.h @@ -119,9 +119,6 @@ static inline int test_and_set_bit(unsigned int nr, volatile void *addr) (volatile unsigned int *)addr + BITOP_WORD(nr)) != 0; } -#define flsl(x) generic_flsl(x) -#define fls(x) generic_fls(x) - /* Based on linux/include/asm-generic/bitops/ffz.h */ /* * ffz - find first zero in word. diff --git a/xen/arch/x86/include/asm/bitops.h b/xen/arch/x86/include/asm/bitops.h index 23f09fdb7a..8f3d76fe44 100644 --- a/xen/arch/x86/include/asm/bitops.h +++ b/xen/arch/x86/include/asm/bitops.h @@ -425,7 +425,7 @@ static always_inline unsigned int arch_ffsl(unsigned long x) * * This is defined the same way as ffs. */ -static inline int flsl(unsigned long x) +static always_inline int arch_flsl(unsigned long x) { long r; @@ -435,8 +435,9 @@ static inline int flsl(unsigned long x) "1:" : "=r" (r) : "rm" (x)); return (int)r+1; } +#define arch_flsl arch_flsl -static inline int fls(unsigned int x) +static always_inline int arch_fls(unsigned int x) { int r; @@ -446,6 +447,7 @@ static inline int fls(unsigned int x) "1:" : "=r" (r) : "rm" (x)); return r + 1; } +#define arch_fls arch_fls /** * hweightN - returns the hamming weight of a N-bit word diff --git a/xen/common/bitops.c b/xen/common/bitops.c index a8c32f6767..95bc47176b 100644 --- a/xen/common/bitops.c +++ b/xen/common/bitops.c @@ -62,9 +62,31 @@ static void test_ffs(void) CHECK(ffs64, (uint64_t)0x8000000000000000, 64); } +static void test_fls(void) +{ + /* unsigned int ffs(unsigned int) */ + CHECK(fls, 1, 1); + CHECK(fls, 3, 2); + CHECK(fls, 3U << 30, 32); + + /* unsigned int flsl(unsigned long) */ + CHECK(flsl, 1, 1); + CHECK(flsl, 1UL << (BITS_PER_LONG - 1), BITS_PER_LONG); +#if BITS_PER_LONG > 32 + CHECK(flsl, 3UL << 32, 34); +#endif + + /* unsigned int fls64(uint64_t) */ + CHECK(fls64, 1, 1); + CHECK(fls64, 0x00000000C0000000ULL, 32); + CHECK(fls64, 0x0000000180000000ULL, 33); + CHECK(fls64, 0xC000000000000000ULL, 64); +} + static int __init cf_check test_bitops(void) { test_ffs(); + test_fls(); return 0; } diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index be4ba3962a..eed6b2a901 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -1842,7 +1842,7 @@ static void _init_heap_pages(const struct page_info *pg, * Note that the value of ffsl() and flsl() starts from 1 so we need * to decrement it by 1. */ - unsigned int inc_order = min(MAX_ORDER, flsl(e - s) - 1); + unsigned int inc_order = min(MAX_ORDER + 0U, flsl(e - s) - 1); if ( s ) inc_order = min(inc_order, ffsl(s) - 1U); @@ -2266,7 +2266,7 @@ void __init xenheap_max_mfn(unsigned long mfn) ASSERT(!first_node_initialised); ASSERT(!xenheap_bits); BUILD_BUG_ON((PADDR_BITS - PAGE_SHIFT) >= BITS_PER_LONG); - xenheap_bits = min(flsl(mfn + 1) - 1 + PAGE_SHIFT, PADDR_BITS); + xenheap_bits = min(flsl(mfn + 1) - 1 + PAGE_SHIFT, PADDR_BITS + 0U); printk(XENLOG_INFO "Xen heap: %u bits\n", xenheap_bits); } diff --git a/xen/include/xen/bitops.h b/xen/include/xen/bitops.h index 4f3399273a..f5be10b928 100644 --- a/xen/include/xen/bitops.h +++ b/xen/include/xen/bitops.h @@ -203,6 +203,30 @@ static always_inline bool test_bit(int nr, const volatile void *addr) test_bit(nr, addr); \ }) +static always_inline __pure unsigned int fls(unsigned int x) +{ + if ( __builtin_constant_p(x) ) + return generic_fls(x); + +#ifndef arch_fls +#define arch_fls generic_fls +#endif + + return arch_fls(x); +} + +static always_inline __pure unsigned int flsl(unsigned long x) +{ + if ( __builtin_constant_p(x) ) + return generic_flsl(x); + +#ifndef arch_flsl +#define arch_flsl generic_flsl +#endif + + return arch_flsl(x); +} + /* * Find First Set bit. Bits are labelled from 1. */ -- 2.45.0
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