Implement runtime library for riscv
Some unused methods remain unimplemented for now.
Bug: 352784623
Test: inline_asm_tests
Change-Id: I4de39dfccfc6ce8f4c78961abe79ece03aa7ce53
diff --git a/runtime/runtime_library_riscv64.cc b/runtime/runtime_library_riscv64.cc
index 5721e1d..94f36bc 100644
--- a/runtime/runtime_library_riscv64.cc
+++ b/runtime/runtime_library_riscv64.cc
@@ -16,15 +16,120 @@
#include "berberis/runtime_primitives/runtime_library.h"
-// TODO: b/352784623 - These need to be implemented by the time we activate
-// translation cache.
+#include "berberis/base/config.h"
+#include "berberis/guest_state/guest_state.h"
+
+extern "C" void berberis_HandleNotTranslated(berberis::ThreadState* state);
+
+// We define a helper method in order to bring berberis_HandleNotTranslated into the PLT.
+__attribute__((used, __visibility__("hidden"))) extern "C" void helper_NotTranslated(
+ berberis::ThreadState* state) {
+ berberis_HandleNotTranslated(state);
+}
+
+// Perform all the steps needed to exit generated code except return, which is
+// up to the users of this macro. The users of this macro may choose to perform
+// a sibling call as necessary.
+// clang-format off
+#define END_GENERATED_CODE(EXIT_INSN) \
+ asm( \
+ /* Sync insn_addr. */ \
+ "sd s11, %[InsnAddr](fp)\n" \
+ /* Set kOutsideGeneratedCode residence. */ \
+ "li t1, %[OutsideGeneratedCode]\n" \
+ "sb t1, %[Residence](fp)\n" \
+ \
+ /* Set a0 to the pointer to the guest state so that \
+ * we can perform a sibling call to functions like \
+ * berberis_HandleNotTranslated. \
+ */ \
+ "mv a0, fp\n" \
+ \
+ /* Epilogue */ \
+ "ld fp, 88(sp)\n" \
+ "ld s1, 80(sp)\n" \
+ "ld s2, 72(sp)\n" \
+ "ld s3, 64(sp)\n" \
+ "ld s4, 56(sp)\n" \
+ "ld s5, 48(sp)\n" \
+ "ld s6, 40(sp)\n" \
+ "ld s7, 32(sp)\n" \
+ "ld s8, 24(sp)\n" \
+ "ld s9, 16(sp)\n" \
+ "ld s10, 8(sp)\n" \
+ "ld s11, 0(sp)\n" \
+ "addi sp, sp, 96\n" \
+ \
+ EXIT_INSN \
+ ::[InsnAddr] "I"(offsetof(berberis::ThreadState, cpu.insn_addr)), \
+ [Residence] "I"(offsetof(berberis::ThreadState, residence)), \
+ [OutsideGeneratedCode] "I"(berberis::kOutsideGeneratedCode))
+// clang-format on
namespace berberis {
extern "C" {
[[gnu::naked]] [[gnu::noinline]] void berberis_RunGeneratedCode(ThreadState* state, HostCode code) {
- asm("unimp");
+ // Parameters are in a0 - state and a1 - code.
+ // Instruction address is saved in s11. This is also the last register to be allocated within a
+ // region. This approach maximizes the chance of s11 being not clobbered and thus facilitates
+ // debugging.
+ //
+ // On riscv64 Linux, stack should be aligned on 16 at every call insn.
+ // That means stack is always 0 mod 16 on function entry.
+ // See https://riscv.org/wp-content/uploads/2015/01/riscv-calling.pdf (18.2).
+ //
+ // We are saving all general purpose callee saved registers.
+ // TODO(b/352784623): Save fp registers when we start using them.
+ //
+ // Stack:
+ // 0: saved s11 <- stack after prologue
+ // 8: saved s10
+ // 16: saved s9
+ // 24: saved s8
+ // 32: saved s7
+ // 40: saved s6
+ // 48: saved s5
+ // 56: saved s4
+ // 64: saved s3
+ // 72: saved s2
+ // 80: saved s1
+ // 88: saved fp(s0)
+ // 96: <- stack at call insn - aligned on 16
+
+ // clang-format off
+ asm(
+ // Prologue
+ "addi sp, sp, -96\n"
+ "sd s11, 0(sp)\n"
+ "sd s10, 8(sp)\n"
+ "sd s9, 16(sp)\n"
+ "sd s8, 24(sp)\n"
+ "sd s7, 32(sp)\n"
+ "sd s6, 40(sp)\n"
+ "sd s5, 48(sp)\n"
+ "sd s4, 56(sp)\n"
+ "sd s3, 64(sp)\n"
+ "sd s2, 72(sp)\n"
+ "sd s1, 80(sp)\n"
+ "sd fp, 88(sp)\n"
+
+ // Set state pointer.
+ "mv fp, a0\n" // kStateRegister, kOmitFramePointer
+
+ // Set insn_addr.
+ "ld s11, %[InsnAddr](fp)\n"
+ // Set kInsideGeneratedCode residence.
+ "li t1, %[InsideGeneratedCode]\n"
+ "sb t1, %[Residence](fp)\n"
+
+ // Jump to entry.
+ "jr a1\n"
+ ::[InsnAddr] "I"(offsetof(ThreadState, cpu.insn_addr)),
+ [Residence] "I"(offsetof(ThreadState, residence)),
+ [InsideGeneratedCode] "I"(kInsideGeneratedCode));
+ // clang-format on
}
[[gnu::naked]] [[gnu::noinline]] void berberis_entry_Interpret() {
@@ -32,11 +137,11 @@
}
[[gnu::naked]] [[gnu::noinline]] void berberis_entry_ExitGeneratedCode() {
- asm("unimp");
+ END_GENERATED_CODE("ret");
}
[[gnu::naked]] [[gnu::noinline]] void berberis_entry_Stop() {
- asm("unimp");
+ END_GENERATED_CODE("ret");
}
[[gnu::naked]] [[gnu::noinline]] void berberis_entry_NoExec() {
@@ -44,7 +149,8 @@
}
[[gnu::naked]] [[gnu::noinline]] void berberis_entry_NotTranslated() {
- asm("unimp");
+ // @plt is needed since the symbol is dynamically linked.
+ END_GENERATED_CODE("tail berberis_HandleNotTranslated@plt");
}
[[gnu::naked]] [[gnu::noinline]] void berberis_entry_Translating() {
