From daba25d6e09e923ca4458211ca086eeb8bef8b5a Mon Sep 17 00:00:00 2001 From: Lv Zheng Date: Wed, 16 Jul 2014 16:58:00 +0800 Subject: [PATCH] ACPICA: Linux: Add stub implementation of ACPICA 64-bit mathematics. This patch adds default 64-bit mathematics in aclinux.h using do_div(). As do_div() can be used for all Linux architectures, this can also be used as stub macros for ACPICA 64-bit mathematics. These macros are required by drivers/acpi/utmath.c when ACPI_USE_NATIVE_DIVIDE is not defined. It is used by ACPICA, so currently this is only meaningful to CONFIG_ACPI builds. So the kernel will not use these macros unless CONFIG_ACPI is defined and ACPI_USE_DIVIDE is not defined. For 64-bit kernels: In include/acpi/actypes.h, for ACPI_MACHINE_WIDTH=64, ACPI_USE_NATIVE_DIVIDE will be defined, thus these macros are not used. In include/acpi/platform/aclinux.h, for __KERNEL__ surrounded code, ACPI_MACHINE_WIDTH is defined to be BITS_PER_LONG. So all 64-bit kernels do not use these macros. For 32-bit kernels: As mentioned above, these macros will be used when BITS_PER_LONG is 32. Thus currently the i328 kernels are the only users for these macros. But they won't use this default implementation provided by this patch, because in arch/x86/include/asm/acenv.h, there are already overrides implemented. So these default macros are not used by 32-bit x86 (i386) kernels. These macros will only be used by future non x86 32-bit architectures that try to support ACPI in Linux kernel. During the period they do not have arch specific implementations of such macros, we can avoid build errors for them. And since they can see ACPICA functioning without implementing any arch specific environment tunings, we can also avoid function errors for them. As this implementation is not performance friendly, those architectures still need to implement real support in the end. Signed-off-by: Lv Zheng [rjw: Changelog] Signed-off-by: Rafael J. Wysocki --- include/acpi/platform/aclinuxex.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/include/acpi/platform/aclinuxex.h b/include/acpi/platform/aclinuxex.h index 191e741cfa0e..568d4b886712 100644 --- a/include/acpi/platform/aclinuxex.h +++ b/include/acpi/platform/aclinuxex.h @@ -46,6 +46,28 @@ #ifdef __KERNEL__ +#ifndef ACPI_USE_NATIVE_DIVIDE + +#ifndef ACPI_DIV_64_BY_32 +#define ACPI_DIV_64_BY_32(n_hi, n_lo, d32, q32, r32) \ + do { \ + u64 (__n) = ((u64) n_hi) << 32 | (n_lo); \ + (r32) = do_div ((__n), (d32)); \ + (q32) = (u32) (__n); \ + } while (0) +#endif + +#ifndef ACPI_SHIFT_RIGHT_64 +#define ACPI_SHIFT_RIGHT_64(n_hi, n_lo) \ + do { \ + (n_lo) >>= 1; \ + (n_lo) |= (((n_hi) & 1) << 31); \ + (n_hi) >>= 1; \ + } while (0) +#endif + +#endif + /* * Overrides for in-kernel ACPICA */ -- 2.20.1