cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

stacktrace.c (2667B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/kernel.h>
      3
      4typedef unsigned int instr;
      5
      6#define MAJOR_OP	0xfc000000
      7#define LDA_OP		0x20000000
      8#define STQ_OP		0xb4000000
      9#define BR_OP		0xc0000000
     10
     11#define STK_ALLOC_1	0x23de8000 /* lda $30,-X($30) */
     12#define STK_ALLOC_1M	0xffff8000
     13#define STK_ALLOC_2	0x43c0153e /* subq $30,X,$30 */
     14#define STK_ALLOC_2M	0xffe01fff
     15
     16#define MEM_REG		0x03e00000
     17#define MEM_BASE	0x001f0000
     18#define MEM_OFF		0x0000ffff
     19#define MEM_OFF_SIGN	0x00008000
     20#define	BASE_SP		0x001e0000
     21
     22#define STK_ALLOC_MATCH(INSTR)			\
     23  (((INSTR) & STK_ALLOC_1M) == STK_ALLOC_1	\
     24   || ((INSTR) & STK_ALLOC_2M) == STK_ALLOC_2)
     25#define STK_PUSH_MATCH(INSTR) \
     26  (((INSTR) & (MAJOR_OP | MEM_BASE | MEM_OFF_SIGN)) == (STQ_OP | BASE_SP))
     27#define MEM_OP_OFFSET(INSTR) \
     28  (((long)((INSTR) & MEM_OFF) << 48) >> 48)
     29#define MEM_OP_REG(INSTR) \
     30  (((INSTR) & MEM_REG) >> 22)
     31
     32/* Branches, jumps, PAL calls, and illegal opcodes end a basic block. */
     33#define BB_END(INSTR)						\
     34  (((instr)(INSTR) >= BR_OP) | ((instr)(INSTR) < LDA_OP) |	\
     35   ((((instr)(INSTR) ^ 0x60000000) < 0x20000000) &		\
     36    (((instr)(INSTR) & 0x0c000000) != 0)))
     37
     38#define IS_KERNEL_TEXT(PC) ((unsigned long)(PC) > START_ADDR)
     39
     40static char reg_name[][4] = {
     41	"v0 ", "t0 ", "t1 ", "t2 ", "t3 ", "t4 ", "t5 ", "t6 ", "t7 ",
     42	"s0 ", "s1 ", "s2 ", "s3 ", "s4 ", "s5 ", "s6 ", "a0 ", "a1 ",
     43	"a2 ", "a3 ", "a4 ", "a5 ", "t8 ", "t9 ", "t10", "t11", "ra ",
     44	"pv ", "at ", "gp ", "sp ", "0"
     45};
     46
     47
     48static instr *
     49display_stored_regs(instr * pro_pc, unsigned char * sp)
     50{
     51	instr * ret_pc = 0;
     52	int reg;
     53	unsigned long value;
     54
     55	printk("Prologue [<%p>], Frame %p:\n", pro_pc, sp);
     56	while (!BB_END(*pro_pc))
     57		if (STK_PUSH_MATCH(*pro_pc)) {
     58			reg = (*pro_pc & MEM_REG) >> 21;
     59			value = *(unsigned long *)(sp + (*pro_pc & MEM_OFF));
     60			if (reg == 26)
     61				ret_pc = (instr *)value;
     62			printk("\t\t%s / 0x%016lx\n", reg_name[reg], value);
     63		}
     64	return ret_pc;
     65}
     66
     67static instr *
     68seek_prologue(instr * pc)
     69{
     70	while (!STK_ALLOC_MATCH(*pc))
     71		--pc;
     72	while (!BB_END(*(pc - 1)))
     73		--pc;
     74	return pc;
     75}
     76
     77static long
     78stack_increment(instr * prologue_pc)
     79{
     80	while (!STK_ALLOC_MATCH(*prologue_pc))
     81		++prologue_pc;
     82
     83	/* Count the bytes allocated. */
     84	if ((*prologue_pc & STK_ALLOC_1M) == STK_ALLOC_1M)
     85		return -(((long)(*prologue_pc) << 48) >> 48);
     86	else
     87		return (*prologue_pc >> 13) & 0xff;
     88}
     89
     90void
     91stacktrace(void)
     92{
     93	instr * ret_pc;
     94	instr * prologue = (instr *)stacktrace;
     95	register unsigned char * sp __asm__ ("$30");
     96
     97	printk("\tstack trace:\n");
     98	do {
     99		ret_pc = display_stored_regs(prologue, sp);
    100		sp += stack_increment(prologue);
    101		prologue = seek_prologue(ret_pc);
    102	} while (IS_KERNEL_TEXT(ret_pc));
    103}