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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v11 3/9] 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.
The prototype of the per-architecture fls{l}() functions was changed to
return 'unsigned int' to align with the generic implementation of these
functions and avoid introducing signed/unsigned mismatches.
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
The current one patch can be merged w/o waiting of Andrew's patch series.
Andrew C. could you please consider the following patch to be as a part of
your bit operation
patch series if your patch series will be in staging before mine:
https://gitlab.com/xen-project/people/olkur/xen/-/commit/24a346c7aa4f51ba34eacb7bfee2808e431daf00
Thanks in advance.
---
Changes in V11:
- drop unnessary case and fix code style for x86's arch_flsl()
- rebase on top of staging, so it can be merged to staging if necessary
apporves will be given
- move changes related to fls related function to separate patch on top of
Andrew's patch series
as the C file with tests is introduced in his patch series. The patch is
mentioned in footer.
---
Changes in V10:
- update return type of arch_flsl() across arcitectures to 'unsigned int' to
be aligned
with return type of generic flsl() in xen/bitops.h.
- switch inline to always_inline for arch_flsl() across architectures to be in
sync
with other similar changes.
- define arch_flsl as arch_fls not just only fls.
- update the commit message ( add information that per-arch fls{l)() protypes
were
changed ).
---
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 | 9 +++------
xen/arch/ppc/include/asm/bitops.h | 2 --
xen/arch/x86/include/asm/bitops.h | 12 +++++++-----
xen/common/page_alloc.c | 4 ++--
xen/include/xen/bitops.h | 24 ++++++++++++++++++++++++
7 files changed, 39 insertions(+), 20 deletions(-)
diff --git a/xen/arch/arm/include/asm/arm32/bitops.h
b/xen/arch/arm/include/asm/arm32/bitops.h
index d0309d47c1..9ee96f568b 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 arch_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 906d84e5f2..d942077392 100644
--- a/xen/arch/arm/include/asm/arm64/bitops.h
+++ b/xen/arch/arm/include/asm/arm64/bitops.h
@@ -1,17 +1,15 @@
#ifndef _ARM_ARM64_BITOPS_H
#define _ARM_ARM64_BITOPS_H
-static inline int flsl(unsigned long x)
+static always_inline unsigned 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 af38fbffdd..52fd33a797 100644
--- a/xen/arch/arm/include/asm/bitops.h
+++ b/xen/arch/arm/include/asm/bitops.h
@@ -76,17 +76,14 @@ 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 always_inline unsigned int arch_fls(unsigned int x)
{
- int ret;
-
- if (__builtin_constant_p(x))
- return generic_fls(x);
+ unsigned int ret;
asm("clz\t%"__OP32"0, %"__OP32"1" : "=r" (ret) : "r" (x));
return 32 - ret;
}
-
+#define arch_fls arch_fls
#define ffs(x) ({ unsigned int __t = (x); fls(ISOLATE_LSB(__t)); })
#define 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 71bbb5f16a..82f9d92c7a 100644
--- a/xen/arch/ppc/include/asm/bitops.h
+++ b/xen/arch/ppc/include/asm/bitops.h
@@ -117,8 +117,6 @@ 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)
#define ffs(x) ({ unsigned int t_ = (x); fls(t_ & -t_); })
#define ffsl(x) ({ unsigned long t_ = (x); flsl(t_ & -t_); })
diff --git a/xen/arch/x86/include/asm/bitops.h
b/xen/arch/x86/include/asm/bitops.h
index c4e7a06155..e488b39728 100644
--- a/xen/arch/x86/include/asm/bitops.h
+++ b/xen/arch/x86/include/asm/bitops.h
@@ -434,20 +434,21 @@ static inline int ffs(unsigned int x)
*
* This is defined the same way as ffs.
*/
-static inline int flsl(unsigned long x)
+static always_inline unsigned int arch_flsl(unsigned long x)
{
- long r;
+ unsigned long r;
asm ( "bsr %1,%0\n\t"
"jnz 1f\n\t"
"mov $-1,%0\n"
"1:" : "=r" (r) : "rm" (x));
- return (int)r+1;
+ return r + 1;
}
+#define arch_flsl arch_flsl
-static inline int fls(unsigned int x)
+static always_inline unsigned int arch_fls(unsigned int x)
{
- int r;
+ unsigned int r;
asm ( "bsr %1,%0\n\t"
"jnz 1f\n\t"
@@ -455,6 +456,7 @@ 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/page_alloc.c b/xen/common/page_alloc.c
index 7c1bdfc046..d4d05d02b7 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 9f89232ba6..c98eb827e3 100644
--- a/xen/include/xen/bitops.h
+++ b/xen/include/xen/bitops.h
@@ -290,6 +290,30 @@ 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);
+}
+
#ifndef find_next_bit
/**
* find_next_bit - find the next set bit in a memory region
--
2.45.0
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