cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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static_call.c (949B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/memory.h>
      3#include <linux/static_call.h>
      4
      5#include <asm/code-patching.h>
      6
      7void arch_static_call_transform(void *site, void *tramp, void *func, bool tail)
      8{
      9	int err;
     10	bool is_ret0 = (func == __static_call_return0);
     11	unsigned long target = (unsigned long)(is_ret0 ? tramp + PPC_SCT_RET0 : func);
     12	bool is_short = is_offset_in_branch_range((long)target - (long)tramp);
     13
     14	if (!tramp)
     15		return;
     16
     17	mutex_lock(&text_mutex);
     18
     19	if (func && !is_short) {
     20		err = patch_instruction(tramp + PPC_SCT_DATA, ppc_inst(target));
     21		if (err)
     22			goto out;
     23	}
     24
     25	if (!func)
     26		err = patch_instruction(tramp, ppc_inst(PPC_RAW_BLR()));
     27	else if (is_short)
     28		err = patch_branch(tramp, target, 0);
     29	else
     30		err = patch_instruction(tramp, ppc_inst(PPC_RAW_NOP()));
     31out:
     32	mutex_unlock(&text_mutex);
     33
     34	if (err)
     35		panic("%s: patching failed %pS at %pS\n", __func__, func, tramp);
     36}
     37EXPORT_SYMBOL_GPL(arch_static_call_transform);