From b4f2e2ad5348063ef94aa623f6f09b52ecaf0990 Mon Sep 17 00:00:00 2001 From: John David Anglin Date: Sun, 2 Aug 2009 12:34:08 +0200 Subject: [PATCH] parisc: Fix GOT overflow during module load on 64bit kernel Signed-off-by: John David Anglin Signed-off-by: Helge Deller --- arch/parisc/kernel/module.c | 50 +++++++++++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 5 deletions(-) diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c index ef5caf2e6ed0..61ee0eec4e69 100644 --- a/arch/parisc/kernel/module.c +++ b/arch/parisc/kernel/module.c @@ -86,8 +86,12 @@ * the bottom of the table, which has a maximum signed displacement of * 0x3fff; however, since we're only going forward, this becomes * 0x1fff, and thus, since each GOT entry is 8 bytes long we can have - * at most 1023 entries */ -#define MAX_GOTS 1023 + * at most 1023 entries. + * To overcome this 14bit displacement with some kernel modules, we'll + * use instead the unusal 16bit displacement method (see reassemble_16a) + * which gives us a maximum positive displacement of 0x7fff, and as such + * allows us to allocate up to 4095 GOT entries. */ +#define MAX_GOTS 4095 /* three functions to determine where in the module core * or init pieces the location is */ @@ -145,12 +149,40 @@ struct stub_entry { /* The reassemble_* functions prepare an immediate value for insertion into an opcode. pa-risc uses all sorts of weird bitfields in the instruction to hold the value. */ +static inline int sign_unext(int x, int len) +{ + int len_ones; + + len_ones = (1 << len) - 1; + return x & len_ones; +} + +static inline int low_sign_unext(int x, int len) +{ + int sign, temp; + + sign = (x >> (len-1)) & 1; + temp = sign_unext(x, len-1); + return (temp << 1) | sign; +} + static inline int reassemble_14(int as14) { return (((as14 & 0x1fff) << 1) | ((as14 & 0x2000) >> 13)); } +static inline int reassemble_16a(int as16) +{ + int s, t; + + /* Unusual 16-bit encoding, for wide mode only. */ + t = (as16 << 1) & 0xffff; + s = (as16 & 0x8000); + return (t ^ s ^ (s >> 1)) | (s >> 15); +} + + static inline int reassemble_17(int as17) { return (((as17 & 0x10000) >> 16) | @@ -407,6 +439,7 @@ static Elf_Addr get_stub(struct module *me, unsigned long value, long addend, enum elf_stub_type stub_type, Elf_Addr loc0, unsigned int targetsec) { struct stub_entry *stub; + int __maybe_unused d; /* initialize stub_offset to point in front of the section */ if (!me->arch.section[targetsec].stub_offset) { @@ -460,12 +493,19 @@ static Elf_Addr get_stub(struct module *me, unsigned long value, long addend, */ switch (stub_type) { case ELF_STUB_GOT: - stub->insns[0] = 0x537b0000; /* ldd 0(%dp),%dp */ + d = get_got(me, value, addend); + if (d <= 15) { + /* Format 5 */ + stub->insns[0] = 0x0f6010db; /* ldd 0(%dp),%dp */ + stub->insns[0] |= low_sign_unext(d, 5) << 16; + } else { + /* Format 3 */ + stub->insns[0] = 0x537b0000; /* ldd 0(%dp),%dp */ + stub->insns[0] |= reassemble_16a(d); + } stub->insns[1] = 0x53610020; /* ldd 10(%dp),%r1 */ stub->insns[2] = 0xe820d000; /* bve (%r1) */ stub->insns[3] = 0x537b0030; /* ldd 18(%dp),%dp */ - - stub->insns[0] |= reassemble_14(get_got(me, value, addend) & 0x3fff); break; case ELF_STUB_MILLI: stub->insns[0] = 0x20200000; /* ldil 0,%r1 */ -- 2.30.2