| Message ID | 20181116225558.27720-2-ard.biesheuvel@linaro.org |
|---|---|
| State | Accepted |
| Commit | 0bcf71c13c8ce9ad254da901420badb74420a6df |
| Headers | show |
| Series | Clear frame pointer in startup code on AARCH64 systems | expand |
diff --git a/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S b/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S index 0950fd0c0cdb..dc52e1138199 100644 --- a/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S +++ b/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S @@ -76,6 +76,9 @@ _PrepareArguments: // Ensure we're jumping to FV version of the code (not boot remapped alias) ldr x3, =ASM_PFX(CEntryPoint) + // Set the frame pointer to 0x0 so any backtraces terminate here + mov x29, xzr + // Jump to PrePeiCore C code // x0 = mp_id // x1 = pei_core_address diff --git a/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S b/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S index a81709d5d12d..8db022dcf05e 100644 --- a/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S +++ b/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S @@ -109,6 +109,9 @@ _PrepareArguments: // Ensure we're jumping to FV version of the code (not boot remapped alias) ldr x4, =ASM_PFX(CEntryPoint) + // Set the frame pointer to 0x0 so any backtraces terminate here + mov x29, xzr + // Jump to PrePiCore C code // x0 = MpId // x1 = UefiMemoryBase
When setting up the stack in the startup code and jumping into C code for the first time, ensure that the frame pointer register is cleared so that backtraces terminate correctly. Otherwise, output like the below is shown when encountering an exception on a DEBUG build: Synchronous Exception at 0x0000000078A14780 PC 0x000078A14780 (0x000078A00000+0x00014780) [ 0] ArmVeNorFlashDxe.dll PC 0x000078A10634 (0x000078A00000+0x00010634) [ 0] ArmVeNorFlashDxe.dll PC 0x000078A11CF0 (0x000078A00000+0x00011CF0) [ 0] ArmVeNorFlashDxe.dll PC 0x000078A11DD0 (0x000078A00000+0x00011DD0) [ 0] ArmVeNorFlashDxe.dll PC 0x00007BC9D87C (0x00007BC98000+0x0000587C) [ 1] PartitionDxe.dll PC 0x00007BC99B3C (0x00007BC98000+0x00001B3C) [ 1] PartitionDxe.dll PC 0x00007F362F50 (0x00007F359000+0x00009F50) [ 2] DxeCore.dll PC 0x00007BD63BB0 (0x00007BD5B000+0x00008BB0) [ 3] BdsDxe.dll PC 0x00007BD6EE00 (0x00007BD5B000+0x00013E00) [ 3] BdsDxe.dll PC 0x00007BD67C70 (0x00007BD5B000+0x0000CC70) [ 3] BdsDxe.dll PC 0x00007F3724F0 (0x00007F359000+0x000194F0) [ 4] DxeCore.dll PC 0x00004008FC30 PC 0x000040090130 PC 0x5800F6025800F5E1 Recursive exception occurred while dumping the CPU state which is rather unhelpful, given that this prevent the remaining debug output from being printed (register dump, stack dump, fault related system registers etc) Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S | 3 +++ ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S | 3 +++ 2 files changed, 6 insertions(+) -- 2.17.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel