From f0d1b0b30d250a07627ad8b9fbbb5c7cc08422e8 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 8 Dec 2006 02:37:49 -0800 Subject: [PATCH] LOG2: Implement a general integer log2 facility in the kernel This facility provides three entry points: ilog2() Log base 2 of unsigned long ilog2_u32() Log base 2 of u32 ilog2_u64() Log base 2 of u64 These facilities can either be used inside functions on dynamic data: int do_something(long q) { ...; y = ilog2(x) ...; } Or can be used to statically initialise global variables with constant values: unsigned n = ilog2(27); When performing static initialisation, the compiler will report "error: initializer element is not constant" if asked to take a log of zero or of something not reducible to a constant. They treat negative numbers as unsigned. When not dealing with a constant, they fall back to using fls() which permits them to use arch-specific log calculation instructions - such as BSR on x86/x86_64 or SCAN on FRV - if available. [akpm@osdl.org: MMC fix] Signed-off-by: David Howells Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Herbert Xu Cc: David Howells Cc: Wojtek Kaniewski Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 6738283ac385..3710cce16642 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -13,6 +13,7 @@ #include #include #include +#include #include #include @@ -157,14 +158,6 @@ static inline int printk(const char *s, ...) { return 0; } unsigned long int_sqrt(unsigned long); -static inline int __attribute_pure__ long_log2(unsigned long x) -{ - int r = 0; - for (x >>= 1; x > 0; x >>= 1) - r++; - return r; -} - static inline unsigned long __attribute_const__ roundup_pow_of_two(unsigned long x) { -- cgit v1.2.2 From 312a0c170945b49f319960afd2e492c05f9dd551 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 8 Dec 2006 02:37:51 -0800 Subject: [PATCH] LOG2: Alter roundup_pow_of_two() so that it can use a ilog2() on a constant Alter roundup_pow_of_two() so that it can make use of ilog2() on a constant to produce a constant value, retaining the ability for an arch to override it in the non-const case. This permits the function to be used to initialise variables. Signed-off-by: David Howells Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 6 ------ 1 file changed, 6 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3710cce16642..e8bfac34d2ba 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -158,12 +158,6 @@ static inline int printk(const char *s, ...) { return 0; } unsigned long int_sqrt(unsigned long); -static inline unsigned long -__attribute_const__ roundup_pow_of_two(unsigned long x) -{ - return 1UL << fls_long(x - 1); -} - extern int printk_ratelimit(void); extern int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst); extern bool printk_timed_ratelimit(unsigned long *caller_jiffies, -- cgit v1.2.2 From 8993780a6e44fb4e7ed34e33458506a775356c6e Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 11 Dec 2006 09:28:46 -0800 Subject: Make SLES9 "get_kernel_version" work on the kernel binary again As reported by Andy Whitcroft, at least the SLES9 initrd build process depends on getting the kernel version from the kernel binary. It does that by simply trawling the binary and looking for the signature of the "linux_banner" string (the string "Linux version " to be exact. Which is really broken in itself, but whatever..) That got broken when the string was changed to allow /proc/version to change the UTS release information dynamically, and "get_kernel_version" thus returned "%s" (see commit a2ee8649ba6d71416712e798276bf7c40b64e6e5: "[PATCH] Fix linux banner utsname information"). This just restores "linux_banner" as a static string, which should fix the version finding. And /proc/version simply uses a different string. To avoid wasting even that miniscule amount of memory, the early boot string should really be marked __initdata, but that just causes the same bug in SLES9 to re-appear, since it will then find other occurrences of "Linux version " first. Cc: Andy Whitcroft Acked-by: Herbert Poetzl Cc: Andi Kleen Cc: Andrew Morton Cc: Steve Fox Acked-by: Olaf Hering Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index e8bfac34d2ba..b0c4a05a4b0c 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -17,8 +17,6 @@ #include #include -extern const char linux_banner[]; - #define INT_MAX ((int)(~0U>>1)) #define INT_MIN (-INT_MAX - 1) #define UINT_MAX (~0U) -- cgit v1.2.2 From 3eb3c740f51c2126b53c2dde974c1c57e634aa7b Mon Sep 17 00:00:00 2001 From: Roman Zippel Date: Wed, 10 Jan 2007 14:45:28 +0100 Subject: [PATCH] fix linux banner format string Revert previous attempts at messing with the linux banner string and simply use a separate format string for proc. Signed-off-by: Roman Zippel Acked-by: Olaf Hering Acked-by: Jean Delvare Cc: Andrey Borzenkov Cc: Andrew Morton Cc: Andy Whitcroft Cc: Herbert Poetzl Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index b0c4a05a4b0c..63fb18dcac30 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -17,6 +17,9 @@ #include #include +extern const char linux_banner[]; +extern const char linux_proc_banner[]; + #define INT_MAX ((int)(~0U>>1)) #define INT_MIN (-INT_MAX - 1) #define UINT_MAX (~0U) -- cgit v1.2.2