diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h index 662c7bd06108..e1f07764b0d6 100644 --- a/arch/arm/include/asm/div64.h +++ b/arch/arm/include/asm/div64.h @@ -5,9 +5,9 @@ #include /* - * The semantics of do_div() are: + * The semantics of __div64_32() are: * - * uint32_t do_div(uint64_t *n, uint32_t base) + * uint32_t __div64_32(uint64_t *n, uint32_t base) * { * uint32_t remainder = *n % base; * *n = *n / base; @@ -16,8 +16,9 @@ * * In other words, a 64-bit dividend with a 32-bit divisor producing * a 64-bit result and a 32-bit remainder. To accomplish this optimally - * we call a special __do_div64 helper with completely non standard - * calling convention for arguments and results (beware). + * we override the generic version in lib/div64.c to call our __do_div64 + * assembly implementation with completely non standard calling convention + * for arguments and results (beware). */ #ifdef __ARMEB__ @@ -28,199 +29,101 @@ #define __xh "r1" #endif -#define __do_div_asm(n, base) \ -({ \ - register unsigned int __base asm("r4") = base; \ - register unsigned long long __n asm("r0") = n; \ - register unsigned long long __res asm("r2"); \ - register unsigned int __rem asm(__xh); \ - asm( __asmeq("%0", __xh) \ - __asmeq("%1", "r2") \ - __asmeq("%2", "r0") \ - __asmeq("%3", "r4") \ - "bl __do_div64" \ - : "=r" (__rem), "=r" (__res) \ - : "r" (__n), "r" (__base) \ - : "ip", "lr", "cc"); \ - n = __res; \ - __rem; \ -}) +static inline uint32_t __div64_32(uint64_t *n, uint32_t base) +{ + register unsigned int __base asm("r4") = base; + register unsigned long long __n asm("r0") = *n; + register unsigned long long __res asm("r2"); + register unsigned int __rem asm(__xh); + asm( __asmeq("%0", __xh) + __asmeq("%1", "r2") + __asmeq("%2", "r0") + __asmeq("%3", "r4") + "bl __do_div64" + : "=r" (__rem), "=r" (__res) + : "r" (__n), "r" (__base) + : "ip", "lr", "cc"); + *n = __res; + return __rem; +} +#define __div64_32 __div64_32 -#if __GNUC__ < 4 || !defined(CONFIG_AEABI) +#if !defined(CONFIG_AEABI) + +/* + * In OABI configurations, some uses of the do_div function + * cause gcc to run out of registers. To work around that, + * we can force the use of the out-of-line version for + * configurations that build a OABI kernel. + */ +#define do_div(n, base) __div64_32(&(n), base) + +#else /* * gcc versions earlier than 4.0 are simply too problematic for the - * optimized implementation below. First there is gcc PR 15089 that - * tend to trig on more complex constructs, spurious .global __udivsi3 - * are inserted even if none of those symbols are referenced in the - * generated code, and those gcc versions are not able to do constant - * propagation on long long values anyway. + * __div64_const32() code in asm-generic/div64.h. First there is + * gcc PR 15089 that tend to trig on more complex constructs, spurious + * .global __udivsi3 are inserted even if none of those symbols are + * referenced in the generated code, and those gcc versions are not able + * to do constant propagation on long long values anyway. */ -#define do_div(n, base) __do_div_asm(n, base) -#elif __GNUC__ >= 4 +#define __div64_const32_is_OK (__GNUC__ >= 4) -#include +static inline uint64_t __arch_xprod_64(uint64_t m, uint64_t n, bool bias) +{ + unsigned long long res; + unsigned int tmp = 0; -/* - * If the divisor happens to be constant, we determine the appropriate - * inverse at compile time to turn the division into a few inline - * multiplications instead which is much faster. And yet only if compiling - * for ARMv4 or higher (we need umull/umlal) and if the gcc version is - * sufficiently recent to perform proper long long constant propagation. - * (It is unfortunate that gcc doesn't perform all this internally.) - */ -#define do_div(n, base) \ -({ \ - unsigned int __r, __b = (base); \ - if (!__builtin_constant_p(__b) || __b == 0 || \ - (__LINUX_ARM_ARCH__ < 4 && (__b & (__b - 1)) != 0)) { \ - /* non-constant divisor (or zero): slow path */ \ - __r = __do_div_asm(n, __b); \ - } else if ((__b & (__b - 1)) == 0) { \ - /* Trivial: __b is constant and a power of 2 */ \ - /* gcc does the right thing with this code. */ \ - __r = n; \ - __r &= (__b - 1); \ - n /= __b; \ - } else { \ - /* Multiply by inverse of __b: n/b = n*(p/b)/p */ \ - /* We rely on the fact that most of this code gets */ \ - /* optimized away at compile time due to constant */ \ - /* propagation and only a couple inline assembly */ \ - /* instructions should remain. Better avoid any */ \ - /* code construct that might prevent that. */ \ - unsigned long long __res, __x, __t, __m, __n = n; \ - unsigned int __c, __p, __z = 0; \ - /* preserve low part of n for reminder computation */ \ - __r = __n; \ - /* determine number of bits to represent __b */ \ - __p = 1 << __div64_fls(__b); \ - /* compute __m = ((__p << 64) + __b - 1) / __b */ \ - __m = (~0ULL / __b) * __p; \ - __m += (((~0ULL % __b + 1) * __p) + __b - 1) / __b; \ - /* compute __res = __m*(~0ULL/__b*__b-1)/(__p << 64) */ \ - __x = ~0ULL / __b * __b - 1; \ - __res = (__m & 0xffffffff) * (__x & 0xffffffff); \ - __res >>= 32; \ - __res += (__m & 0xffffffff) * (__x >> 32); \ - __t = __res; \ - __res += (__x & 0xffffffff) * (__m >> 32); \ - __t = (__res < __t) ? (1ULL << 32) : 0; \ - __res = (__res >> 32) + __t; \ - __res += (__m >> 32) * (__x >> 32); \ - __res /= __p; \ - /* Now sanitize and optimize what we've got. */ \ - if (~0ULL % (__b / (__b & -__b)) == 0) { \ - /* those cases can be simplified with: */ \ - __n /= (__b & -__b); \ - __m = ~0ULL / (__b / (__b & -__b)); \ - __p = 1; \ - __c = 1; \ - } else if (__res != __x / __b) { \ - /* We can't get away without a correction */ \ - /* to compensate for bit truncation errors. */ \ - /* To avoid it we'd need an additional bit */ \ - /* to represent __m which would overflow it. */ \ - /* Instead we do m=p/b and n/b=(n*m+m)/p. */ \ - __c = 1; \ - /* Compute __m = (__p << 64) / __b */ \ - __m = (~0ULL / __b) * __p; \ - __m += ((~0ULL % __b + 1) * __p) / __b; \ - } else { \ - /* Reduce __m/__p, and try to clear bit 31 */ \ - /* of __m when possible otherwise that'll */ \ - /* need extra overflow handling later. */ \ - unsigned int __bits = -(__m & -__m); \ - __bits |= __m >> 32; \ - __bits = (~__bits) << 1; \ - /* If __bits == 0 then setting bit 31 is */ \ - /* unavoidable. Simply apply the maximum */ \ - /* possible reduction in that case. */ \ - /* Otherwise the MSB of __bits indicates the */ \ - /* best reduction we should apply. */ \ - if (!__bits) { \ - __p /= (__m & -__m); \ - __m /= (__m & -__m); \ - } else { \ - __p >>= __div64_fls(__bits); \ - __m >>= __div64_fls(__bits); \ - } \ - /* No correction needed. */ \ - __c = 0; \ - } \ - /* Now we have a combination of 2 conditions: */ \ - /* 1) whether or not we need a correction (__c), and */ \ - /* 2) whether or not there might be an overflow in */ \ - /* the cross product (__m & ((1<<63) | (1<<31))) */ \ - /* Select the best insn combination to perform the */ \ - /* actual __m * __n / (__p << 64) operation. */ \ - if (!__c) { \ - asm ( "umull %Q0, %R0, %Q1, %Q2\n\t" \ - "mov %Q0, #0" \ - : "=&r" (__res) \ - : "r" (__m), "r" (__n) \ - : "cc" ); \ - } else if (!(__m & ((1ULL << 63) | (1ULL << 31)))) { \ - __res = __m; \ - asm ( "umlal %Q0, %R0, %Q1, %Q2\n\t" \ - "mov %Q0, #0" \ - : "+&r" (__res) \ - : "r" (__m), "r" (__n) \ - : "cc" ); \ - } else { \ - asm ( "umull %Q0, %R0, %Q1, %Q2\n\t" \ - "cmn %Q0, %Q1\n\t" \ - "adcs %R0, %R0, %R1\n\t" \ - "adc %Q0, %3, #0" \ - : "=&r" (__res) \ - : "r" (__m), "r" (__n), "r" (__z) \ - : "cc" ); \ - } \ - if (!(__m & ((1ULL << 63) | (1ULL << 31)))) { \ - asm ( "umlal %R0, %Q0, %R1, %Q2\n\t" \ - "umlal %R0, %Q0, %Q1, %R2\n\t" \ - "mov %R0, #0\n\t" \ - "umlal %Q0, %R0, %R1, %R2" \ - : "+&r" (__res) \ - : "r" (__m), "r" (__n) \ - : "cc" ); \ - } else { \ - asm ( "umlal %R0, %Q0, %R2, %Q3\n\t" \ - "umlal %R0, %1, %Q2, %R3\n\t" \ - "mov %R0, #0\n\t" \ - "adds %Q0, %1, %Q0\n\t" \ - "adc %R0, %R0, #0\n\t" \ - "umlal %Q0, %R0, %R2, %R3" \ - : "+&r" (__res), "+&r" (__z) \ - : "r" (__m), "r" (__n) \ - : "cc" ); \ - } \ - __res /= __p; \ - /* The reminder can be computed with 32-bit regs */ \ - /* only, and gcc is good at that. */ \ - { \ - unsigned int __res0 = __res; \ - unsigned int __b0 = __b; \ - __r -= __res0 * __b0; \ - } \ - /* BUG_ON(__r >= __b || __res * __b + __r != n); */ \ - n = __res; \ - } \ - __r; \ -}) + if (!bias) { + asm ( "umull %Q0, %R0, %Q1, %Q2\n\t" + "mov %Q0, #0" + : "=&r" (res) + : "r" (m), "r" (n) + : "cc"); + } else if (!(m & ((1ULL << 63) | (1ULL << 31)))) { + res = m; + asm ( "umlal %Q0, %R0, %Q1, %Q2\n\t" + "mov %Q0, #0" + : "+&r" (res) + : "r" (m), "r" (n) + : "cc"); + } else { + asm ( "umull %Q0, %R0, %Q1, %Q2\n\t" + "cmn %Q0, %Q1\n\t" + "adcs %R0, %R0, %R1\n\t" + "adc %Q0, %3, #0" + : "=&r" (res) + : "r" (m), "r" (n), "r" (tmp) + : "cc"); + } -/* our own fls implementation to make sure constant propagation is fine */ -#define __div64_fls(bits) \ -({ \ - unsigned int __left = (bits), __nr = 0; \ - if (__left & 0xffff0000) __nr += 16, __left >>= 16; \ - if (__left & 0x0000ff00) __nr += 8, __left >>= 8; \ - if (__left & 0x000000f0) __nr += 4, __left >>= 4; \ - if (__left & 0x0000000c) __nr += 2, __left >>= 2; \ - if (__left & 0x00000002) __nr += 1; \ - __nr; \ -}) + if (!(m & ((1ULL << 63) | (1ULL << 31)))) { + asm ( "umlal %R0, %Q0, %R1, %Q2\n\t" + "umlal %R0, %Q0, %Q1, %R2\n\t" + "mov %R0, #0\n\t" + "umlal %Q0, %R0, %R1, %R2" + : "+&r" (res) + : "r" (m), "r" (n) + : "cc"); + } else { + asm ( "umlal %R0, %Q0, %R2, %Q3\n\t" + "umlal %R0, %1, %Q2, %R3\n\t" + "mov %R0, #0\n\t" + "adds %Q0, %1, %Q0\n\t" + "adc %R0, %R0, #0\n\t" + "umlal %Q0, %R0, %R2, %R3" + : "+&r" (res), "+&r" (tmp) + : "r" (m), "r" (n) + : "cc"); + } + + return res; +} +#define __arch_xprod_64 __arch_xprod_64 + +#include #endif diff --git a/drivers/clk/tegra/clk-divider.c b/drivers/clk/tegra/clk-divider.c index 48c83efda4cf..16e0aee14773 100644 --- a/drivers/clk/tegra/clk-divider.c +++ b/drivers/clk/tegra/clk-divider.c @@ -32,7 +32,7 @@ static int get_div(struct tegra_clk_frac_div *divider, unsigned long rate, unsigned long parent_rate) { - s64 divider_ux1 = parent_rate; + u64 divider_ux1 = parent_rate; u8 flags = divider->flags; int mul; @@ -54,7 +54,7 @@ static int get_div(struct tegra_clk_frac_div *divider, unsigned long rate, divider_ux1 -= mul; - if (divider_ux1 < 0) + if ((s64)divider_ux1 < 0) return 0; if (divider_ux1 > get_max_div(divider)) diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c index 19c18b7af28a..dc13c4857e6f 100644 --- a/drivers/gpu/drm/mgag200/mgag200_mode.c +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c @@ -1564,7 +1564,7 @@ static uint32_t mga_vga_calculate_mode_bandwidth(struct drm_display_mode *mode, int bits_per_pixel) { uint32_t total_area, divisor; - int64_t active_area, pixels_per_second, bandwidth; + uint64_t active_area, pixels_per_second, bandwidth; uint64_t bytes_per_pixel = (bits_per_pixel + 7) / 8; divisor = 1024; diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c b/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c index 254094ab7fb8..5da2aa8cc333 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/clk/gk20a.c @@ -141,9 +141,8 @@ gk20a_pllg_calc_rate(struct gk20a_clk *clk) rate = clk->parent_rate * clk->n; divider = clk->m * pl_to_div[clk->pl]; - do_div(rate, divider); - return rate / 2; + return rate / divider / 2; } static int diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c index 58ed8f25ab21..3d5ba5b51af3 100644 --- a/drivers/hid/hid-sensor-hub.c +++ b/drivers/hid/hid-sensor-hub.c @@ -218,7 +218,8 @@ int sensor_hub_set_feature(struct hid_sensor_hub_device *hsdev, u32 report_id, goto done_proc; } - remaining_bytes = do_div(buffer_size, sizeof(__s32)); + remaining_bytes = buffer_size % sizeof(__s32); + buffer_size = buffer_size / sizeof(__s32); if (buffer_size) { for (i = 0; i < buffer_size; ++i) { hid_set_field(report->field[field_index], i, diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h index 8f4e3193342e..163f77999ea4 100644 --- a/include/asm-generic/div64.h +++ b/include/asm-generic/div64.h @@ -4,6 +4,9 @@ * Copyright (C) 2003 Bernardo Innocenti * Based on former asm-ppc/div64.h and asm-m68knommu/div64.h * + * Optimization for constant divisors on 32-bit machines: + * Copyright (C) 2006-2015 Nicolas Pitre + * * The semantics of do_div() are: * * uint32_t do_div(uint64_t *n, uint32_t base) @@ -32,7 +35,168 @@ #elif BITS_PER_LONG == 32 +#include + +/* + * If the divisor happens to be constant, we determine the appropriate + * inverse at compile time to turn the division into a few inline + * multiplications which ought to be much faster. And yet only if compiling + * with a sufficiently recent gcc version to perform proper 64-bit constant + * propagation. + * + * (It is unfortunate that gcc doesn't perform all this internally.) + */ + +#ifndef __div64_const32_is_OK +#define __div64_const32_is_OK (__GNUC__ >= 4) +#endif + +#define __div64_const32(n, ___b) \ +({ \ + /* \ + * Multiplication by reciprocal of b: n / b = n * (p / b) / p \ + * \ + * We rely on the fact that most of this code gets optimized \ + * away at compile time due to constant propagation and only \ + * a few multiplication instructions should remain. \ + * Hence this monstrous macro (static inline doesn't always \ + * do the trick here). \ + */ \ + uint64_t ___res, ___x, ___t, ___m, ___n = (n); \ + uint32_t ___p, ___bias; \ + \ + /* determine MSB of b */ \ + ___p = 1 << ilog2(___b); \ + \ + /* compute m = ((p << 64) + b - 1) / b */ \ + ___m = (~0ULL / ___b) * ___p; \ + ___m += (((~0ULL % ___b + 1) * ___p) + ___b - 1) / ___b; \ + \ + /* one less than the dividend with highest result */ \ + ___x = ~0ULL / ___b * ___b - 1; \ + \ + /* test our ___m with res = m * x / (p << 64) */ \ + ___res = ((___m & 0xffffffff) * (___x & 0xffffffff)) >> 32; \ + ___t = ___res += (___m & 0xffffffff) * (___x >> 32); \ + ___res += (___x & 0xffffffff) * (___m >> 32); \ + ___t = (___res < ___t) ? (1ULL << 32) : 0; \ + ___res = (___res >> 32) + ___t; \ + ___res += (___m >> 32) * (___x >> 32); \ + ___res /= ___p; \ + \ + /* Now sanitize and optimize what we've got. */ \ + if (~0ULL % (___b / (___b & -___b)) == 0) { \ + /* special case, can be simplified to ... */ \ + ___n /= (___b & -___b); \ + ___m = ~0ULL / (___b / (___b & -___b)); \ + ___p = 1; \ + ___bias = 1; \ + } else if (___res != ___x / ___b) { \ + /* \ + * We can't get away without a bias to compensate \ + * for bit truncation errors. To avoid it we'd need an \ + * additional bit to represent m which would overflow \ + * a 64-bit variable. \ + * \ + * Instead we do m = p / b and n / b = (n * m + m) / p. \ + */ \ + ___bias = 1; \ + /* Compute m = (p << 64) / b */ \ + ___m = (~0ULL / ___b) * ___p; \ + ___m += ((~0ULL % ___b + 1) * ___p) / ___b; \ + } else { \ + /* \ + * Reduce m / p, and try to clear bit 31 of m when \ + * possible, otherwise that'll need extra overflow \ + * handling later. \ + */ \ + uint32_t ___bits = -(___m & -___m); \ + ___bits |= ___m >> 32; \ + ___bits = (~___bits) << 1; \ + /* \ + * If ___bits == 0 then setting bit 31 is unavoidable. \ + * Simply apply the maximum possible reduction in that \ + * case. Otherwise the MSB of ___bits indicates the \ + * best reduction we should apply. \ + */ \ + if (!___bits) { \ + ___p /= (___m & -___m); \ + ___m /= (___m & -___m); \ + } else { \ + ___p >>= ilog2(___bits); \ + ___m >>= ilog2(___bits); \ + } \ + /* No bias needed. */ \ + ___bias = 0; \ + } \ + \ + /* \ + * Now we have a combination of 2 conditions: \ + * \ + * 1) whether or not we need to apply a bias, and \ + * \ + * 2) whether or not there might be an overflow in the cross \ + * product determined by (___m & ((1 << 63) | (1 << 31))). \ + * \ + * Select the best way to do (m_bias + m * n) / (1 << 64). \ + * From now on there will be actual runtime code generated. \ + */ \ + ___res = __arch_xprod_64(___m, ___n, ___bias); \ + \ + ___res /= ___p; \ +}) + +#ifndef __arch_xprod_64 +/* + * Default C implementation for __arch_xprod_64() + * + * Prototype: uint64_t __arch_xprod_64(const uint64_t m, uint64_t n, bool bias) + * Semantic: retval = ((bias ? m : 0) + m * n) >> 64 + * + * The product is a 128-bit value, scaled down to 64 bits. + * Assuming constant propagation to optimize away unused conditional code. + * Architectures may provide their own optimized assembly implementation. + */ +static inline uint64_t __arch_xprod_64(const uint64_t m, uint64_t n, bool bias) +{ + uint32_t m_lo = m; + uint32_t m_hi = m >> 32; + uint32_t n_lo = n; + uint32_t n_hi = n >> 32; + uint64_t res, tmp; + + if (!bias) { + res = ((uint64_t)m_lo * n_lo) >> 32; + } else if (!(m & ((1ULL << 63) | (1ULL << 31)))) { + /* there can't be any overflow here */ + res = (m + (uint64_t)m_lo * n_lo) >> 32; + } else { + res = m + (uint64_t)m_lo * n_lo; + tmp = (res < m) ? (1ULL << 32) : 0; + res = (res >> 32) + tmp; + } + + if (!(m & ((1ULL << 63) | (1ULL << 31)))) { + /* there can't be any overflow here */ + res += (uint64_t)m_lo * n_hi; + res += (uint64_t)m_hi * n_lo; + res >>= 32; + } else { + tmp = res += (uint64_t)m_lo * n_hi; + res += (uint64_t)m_hi * n_lo; + tmp = (res < tmp) ? (1ULL << 32) : 0; + res = (res >> 32) + tmp; + } + + res += (uint64_t)m_hi * n_hi; + + return res; +} +#endif + +#ifndef __div64_32 extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor); +#endif /* The unnecessary pointer compare is there * to check for type safety (n must be 64bit) @@ -41,7 +205,19 @@ extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor); uint32_t __base = (base); \ uint32_t __rem; \ (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \ - if (likely(((n) >> 32) == 0)) { \ + if (__builtin_constant_p(__base) && \ + is_power_of_2(__base)) { \ + __rem = (n) & (__base - 1); \ + (n) >>= ilog2(__base); \ + } else if (__div64_const32_is_OK && \ + __builtin_constant_p(__base) && \ + __base != 0) { \ + uint32_t __res_lo, __n_lo = (n); \ + (n) = __div64_const32(n, __base); \ + /* the remainder can be computed with 32-bit regs */ \ + __res_lo = (n); \ + __rem = __n_lo - __res_lo * __base; \ + } else if (likely(((n) >> 32) == 0)) { \ __rem = (uint32_t)(n) % __base; \ (n) = (uint32_t)(n) / __base; \ } else \ diff --git a/lib/div64.c b/lib/div64.c index 62a698a432bc..7f345259c32f 100644 --- a/lib/div64.c +++ b/lib/div64.c @@ -13,7 +13,8 @@ * * Code generated for this function might be very inefficient * for some CPUs. __div64_32() can be overridden by linking arch-specific - * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S. + * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S + * or by defining a preprocessor macro in arch/include/asm/div64.h. */ #include @@ -23,6 +24,7 @@ /* Not needed on 64bit architectures */ #if BITS_PER_LONG == 32 +#ifndef __div64_32 uint32_t __attribute__((weak)) __div64_32(uint64_t *n, uint32_t base) { uint64_t rem = *n; @@ -55,8 +57,8 @@ uint32_t __attribute__((weak)) __div64_32(uint64_t *n, uint32_t base) *n = res; return rem; } - EXPORT_SYMBOL(__div64_32); +#endif #ifndef div_s64_rem s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)