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Ensure SVC trampoline is always correctly sized

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Despite the trampoline size being hardcoded, it was previously dynamic and could change based off of the value stored in the target register potentially leading to instructions being missed.
This commit is contained in:
Billy Laws 2023-04-05 15:06:13 +01:00
parent e0c487f607
commit 5bcc79ef80
1 changed files with 10 additions and 4 deletions
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14
app/src/main/cpp/skyline/nce.cpp
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@ -256,7 +256,7 @@ namespace skyline::nce {
staticNce = nullptr;
}
constexpr size_t TrampolineSize{17}; // Size of the main SVC trampoline function in u32 units
constexpr size_t TrampolineSize{18}; // Size of the main SVC trampoline function in u32 units
/**
* @brief Writes a trampoline to the given target address that saves the current context and calls the given function
@ -280,9 +280,12 @@ namespace skyline::nce {
*code++ = 0xA9BF0BE1; // STP X1, X2, [SP, #-16]!
/* Jump to SvcHandler */
for (const auto &mov : instructions::MoveRegister(registers::X2, target))
for (const auto &mov : instructions::MoveRegister(registers::X2, target)) {
if (mov)
*code++ = mov;
else
*code++ = 0xD503201F; // NOP
}
*code++ = 0xD63F0040; // BLR X2
/* Restore Skyline TLS + guest SP */
@ -297,7 +300,7 @@ namespace skyline::nce {
return code;
}
constexpr size_t RescaleClockSize{17}; //!< The size of the RescaleClock function in 32-bit ARMv8 instructions
constexpr size_t RescaleClockSize{19}; //!< The size of the RescaleClock function in 32-bit ARMv8 instructions
/**
* @brief Writes instructions to rescale the host clock to Tegra X1 levels
@ -316,9 +319,12 @@ namespace skyline::nce {
*code++ = 0xF2E14F80; // MOVK X0, #2684, LSL #48
/* Load clock frequency value */
for (const auto &mov : instructions::MoveRegister(registers::X1, util::ClockFrequency))
for (const auto &mov : instructions::MoveRegister(registers::X1, util::ClockFrequency)) {
if (mov)
*code++ = mov;
else
*code++ = 0xD503201F; // NOP
}
/* Multiply clock frequency by magic constant */
*code++ = 0xD345FC21; // LSR X1, X1, #5