parisc: Fix GOT overflow during module load on 64bit kernel (b4f2e2ad) · Commits · e / devices / android_kernel_xiaomi_markw

arch/parisc/kernel/module.c

+45 −5

Original line number	Original line	Diff line number	Diff line
	@@ -86,8 +86,12 @@
	* the bottom of the table, which has a maximum signed displacement of		* the bottom of the table, which has a maximum signed displacement of
	* 0x3fff; however, since we're only going forward, this becomes		* 0x3fff; however, since we're only going forward, this becomes
	* 0x1fff, and thus, since each GOT entry is 8 bytes long we can have		* 0x1fff, and thus, since each GOT entry is 8 bytes long we can have
	* at most 1023 entries */		* at most 1023 entries.
	#define MAX_GOTS 1023		* 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		/* three functions to determine where in the module core
	* or init pieces the location is */		* or init pieces the location is */
	@@ -145,12 +149,40 @@ struct stub_entry {
	/* The reassemble_* functions prepare an immediate value for		/* The reassemble_* functions prepare an immediate value for
	insertion into an opcode. pa-risc uses all sorts of weird bitfields		insertion into an opcode. pa-risc uses all sorts of weird bitfields
	in the instruction to hold the value. */		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)		static inline int reassemble_14(int as14)
	{		{
	return (((as14 & 0x1fff) << 1) \|		return (((as14 & 0x1fff) << 1) \|
	((as14 & 0x2000) >> 13));		((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)		static inline int reassemble_17(int as17)
	{		{
	return (((as17 & 0x10000) >> 16) \|		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)		enum elf_stub_type stub_type, Elf_Addr loc0, unsigned int targetsec)
	{		{
	struct stub_entry *stub;		struct stub_entry *stub;
			int __maybe_unused d;

	/* initialize stub_offset to point in front of the section */		/* initialize stub_offset to point in front of the section */
	if (!me->arch.section[targetsec].stub_offset) {		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) {		switch (stub_type) {
	case ELF_STUB_GOT:		case ELF_STUB_GOT:
			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] = 0x537b0000; /* ldd 0(%dp),%dp */
			stub->insns[0] \|= reassemble_16a(d);
			}
	stub->insns[1] = 0x53610020; /* ldd 10(%dp),%r1 */		stub->insns[1] = 0x53610020; /* ldd 10(%dp),%r1 */
	stub->insns[2] = 0xe820d000; /* bve (%r1) */		stub->insns[2] = 0xe820d000; /* bve (%r1) */
	stub->insns[3] = 0x537b0030; /* ldd 18(%dp),%dp */		stub->insns[3] = 0x537b0030; /* ldd 18(%dp),%dp */

	stub->insns[0] \|= reassemble_14(get_got(me, value, addend) & 0x3fff);
	break;		break;
	case ELF_STUB_MILLI:		case ELF_STUB_MILLI:
	stub->insns[0] = 0x20200000; /* ldil 0,%r1 */		stub->insns[0] = 0x20200000; /* ldil 0,%r1 */