diff options
Diffstat (limited to 'debian/patches/riscv-rdcycle.diff')
| -rw-r--r-- | debian/patches/riscv-rdcycle.diff | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/debian/patches/riscv-rdcycle.diff b/debian/patches/riscv-rdcycle.diff new file mode 100644 index 00000000..24682c93 --- /dev/null +++ b/debian/patches/riscv-rdcycle.diff @@ -0,0 +1,71 @@ +From: aurel32 <aurelien@aurel32.net> +Subject: unscaledcycleclock: remove RISC-V support +Bug-Debian: https://bugs.debian.org/1059532 +Origin: upstream, https://github.com/abseil/abseil-cpp/commit/7335a36d0b5c1c597566f9aa3f458a5b6817c3b4 + +Starting with Linux 6.6 [1], RDCYCLE is a privileged instruction on +RISC-V and can't be used directly from userland. There is a sysctl +option to change that as a transition period, but it will eventually +disappear. + +The RDTIME instruction is another less accurate alternative, however its +frequency varies from board to board, and there is currently now way to +get its frequency from userland [2]. + +Therefore this patch just removes the code for unscaledcycleclock on +RISC-V. Without processor specific implementation, abseil relies on +std::chrono::steady_clock::now().time_since_epoch() which is basically a +wrapper around clock_gettime (CLOCK_MONOTONIC), which in turns use +__vdso_clock_gettime(). On RISC-V this VDSO is just a wrapper around +RDTIME correctly scaled to use nanoseconds units. + +This fixes the testsuite on riscv64, tested on a VisionFive 2 board. + +[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cc4c07c89aada16229084eeb93895c95b7eabaa3 +[2] https://github.com/abseil/abseil-cpp/pull/1631 + +--- a/absl/base/internal/unscaledcycleclock.cc ++++ b/absl/base/internal/unscaledcycleclock.cc +@@ -121,18 +121,6 @@ + return aarch64_timer_frequency; + } + +-#elif defined(__riscv) +- +-int64_t UnscaledCycleClock::Now() { +- int64_t virtual_timer_value; +- asm volatile("rdcycle %0" : "=r"(virtual_timer_value)); +- return virtual_timer_value; +-} +- +-double UnscaledCycleClock::Frequency() { +- return base_internal::NominalCPUFrequency(); +-} +- + #elif defined(_M_IX86) || defined(_M_X64) + + #pragma intrinsic(__rdtsc) +--- a/absl/base/internal/unscaledcycleclock_config.h ++++ b/absl/base/internal/unscaledcycleclock_config.h +@@ -21,8 +21,8 @@ + + // The following platforms have an implementation of a hardware counter. + #if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \ +- defined(__powerpc__) || defined(__ppc__) || defined(__riscv) || \ +- defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC)) ++ defined(__powerpc__) || defined(__ppc__) || defined(_M_IX86) || \ ++ (defined(_M_X64) && !defined(_M_ARM64EC)) + #define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 1 + #else + #define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 0 +@@ -53,8 +53,8 @@ + #if ABSL_USE_UNSCALED_CYCLECLOCK + // This macro can be used to test if UnscaledCycleClock::Frequency() + // is NominalCPUFrequency() on a particular platform. +-#if (defined(__i386__) || defined(__x86_64__) || defined(__riscv) || \ +- defined(_M_IX86) || defined(_M_X64)) ++#if (defined(__i386__) || defined(__x86_64__) || defined(_M_IX86) || \ ++ defined(_M_X64)) + #define ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY + #endif + #endif |