Messages in this thread | | | Date | Wed, 9 Jan 2019 13:48:53 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v15 1/6] x86/boot: Copy kstrtoull() to boot/string.c instead of using simple_strtoull() |
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On Mon, Jan 07, 2019 at 11:22:38AM +0800, Chao Fan wrote: > Copy kstrtoull() and necessary functions from lib/kstrtox.c to > boot/string.c so that code in boot/ can use kstrtoull() and the old > simple_strtoull() can be replaced. > > In boot/string.c, using div_u64() from math64.h directly will cause the > dividend handled as 64-bit value and bring ld error. The solution is to > separate the dividend to upper and lower in boot/string.o. So copy the > useful div_u64() and div_u64_rem() to boot/string.c also. To avoid > redefinition in i386, rename them as __div_u64() and __div_u64_rem(). > > Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com> > --- > arch/x86/boot/string.c | 137 +++++++++++++++++++++++++++++++++++++++++ > arch/x86/boot/string.h | 2 + > 2 files changed, 139 insertions(+)
...
> +static inline char _tolower(const char c) > +{ > + return c | 0x20; > +} > + > +const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
static
> +{ > + if (*base == 0) { > + if (s[0] == '0') { > + if (_tolower(s[1]) == 'x' && isxdigit(s[2])) > + *base = 16; > + else > + *base = 8; > + } else > + *base = 10; > + } > + if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x') > + s += 2; > + return s; > +} > + > +/* > + * Convert non-negative integer string representation in explicitly given radix > + * to an integer. > + * Return number of characters consumed maybe or-ed with overflow bit. > + * If overflow occurs, result integer (incorrect) is still returned. > + * > + * Don't you dare use this function. > + */ > +unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
static
> +{ > + unsigned long long res; > + unsigned int rv; > + > + res = 0; > + rv = 0; > + while (1) { > + unsigned int c = *s; > + unsigned int lc = c | 0x20; /* don't tolower() this line */ > + unsigned int val; > + > + if ('0' <= c && c <= '9') > + val = c - '0'; > + else if ('a' <= lc && lc <= 'f') > + val = lc - 'a' + 10; > + else > + break; > + > + if (val >= base) > + break; > + /* > + * Check for overflow only if we are within range of > + * it in the max base we support (16) > + */ > + if (unlikely(res & (~0ull << 60))) { > + if (res > __div_u64(ULLONG_MAX - val, base)) > + rv |= KSTRTOX_OVERFLOW; > + } > + res = res * base + val; > + rv++; > + s++; > + } > + *p = res; > + return rv; > +}
-- Regards/Gruss, Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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