Use new linux headers that support ARM (pixie-io#894)

Summary: PR pixie-io#883 added the docker build for an ARM version of linux
headers. This PR pulls those linux headers into our Pixie build.
Which set of merged headers to use is determined by the platform bazel
is building for.

Relevant Issues: pixie-io#147

Type of change: /kind cleanup

Test Plan: Tested a skaffold deploy on each of x86_64 and aarch64.

Signed-off-by: James Bartlett <jamesbartlett@pixielabs.ai>

bazel/linux_headers.bzl

@@ -26,10 +26,16 @@ def linux_headers():
     )
 
     http_file(
-        name = "linux_headers_merged_tar_gz",
-        urls = ["https://storage.googleapis.com/pixie-dev-public/linux-headers/pl5/linux-headers-merged-pl5.tar.gz"],
-        sha256 = "2fa58d4658f0d12c294c72d2ae4410e16968b049e145adde283dcb51a3c148a4",
-        downloaded_file_path = "linux-headers-merged.tar.gz",
+        name = "linux_headers_merged_x86_64_tar_gz",
+        urls = ["https://storage.googleapis.com/pixie-dev-public/linux-headers/pl6/linux-headers-merged-x86_64-pl6.tar.gz"],
+        sha256 = "b99ac9def26c0c1ef03f34583a1e62b96b3b5f8b038428fa582ed28aacbe0ac3",
+        downloaded_file_path = "linux-headers-merged-x86_64.tar.gz",
+    )
+    http_file(
+        name = "linux_headers_merged_arm64_tar_gz",
+        urls = ["https://storage.googleapis.com/pixie-dev-public/linux-headers/pl6/linux-headers-merged-arm64-pl6.tar.gz"],
+        sha256 = "3daa69cc0e0516c2e9190b6c90ed42cbd8cdabc377c30571fc7037354dc5c57f",
+        downloaded_file_path = "linux-headers-merged-arm64.tar.gz",
     )
 
 def gen_timeconst_file(name, const):

src/stirling/BUILD.bazel

@@ -69,9 +69,10 @@ pl_cc_library(
 # Note that each linux header tarball is ~15MB compressed and ~230MB uncompressed.
 # Trimmed versions are ~8MB compressed and ~110MB uncompressed.
 # These are all trimmed versions, so we have 8 * 12 = 96 MB of headers.
-stirling_linux_headers_tarballs = [
-    "@linux_headers_merged_tar_gz//file:file",
-]
+stirling_linux_headers_tarballs = select({
+    "@platforms//cpu:aarch64": ["@linux_headers_merged_arm64_tar_gz//file:file"],
+    "@platforms//cpu:x86_64": ["@linux_headers_merged_x86_64_tar_gz//file:file"],
+})
 
 # Used by stirling runtime to replace the on-the-fly installed Linux headers from
 # stirling_linux_headers_tarballs, in order to match the host's actual configs.

src/stirling/utils/linux_headers.cc

@@ -563,8 +563,15 @@ KernelVersionOrder CompareKernelVersions(KernelVersion a, KernelVersion b) {
 
 StatusOr<PackagedLinuxHeadersSpec> FindClosestPackagedLinuxHeaders(
     const std::filesystem::path& packaged_headers_root, KernelVersion kernel_version) {
+#if X86_64
   const std::string kHeaderDirPrefix =
-      std::filesystem::path(packaged_headers_root / "linux-headers-").string();
+      std::filesystem::path(packaged_headers_root / "linux-headers-x86_64-").string();
+#elif AARCH64
+  const std::string kHeaderDirPrefix =
+      std::filesystem::path(packaged_headers_root / "linux-headers-arm64-").string();
+#else
+#error Architecture not supported
+#endif
   const std::string_view kHeaderDirSuffix = ".tar.gz";
 
   PackagedLinuxHeadersSpec selected;

src/stirling/utils/linux_headers_test.cc

@@ -230,44 +230,41 @@ TEST(LinuxHeadersUtils, FindClosestPackagedLinuxHeaders) {
   const std::string kTestSrcDir =
       testing::BazelRunfilePath("src/stirling/utils/testdata/test_header_packages");
 
+  std::string prefix = "src/stirling/utils/testdata/test_header_packages/linux-headers-";
+#if X86_64
+  prefix = prefix + "x86_64-";
+#elif AARCH64
+  prefix = prefix + "arm64-";
+#endif
+
   {
     ASSERT_OK_AND_ASSIGN(PackagedLinuxHeadersSpec match,
                          FindClosestPackagedLinuxHeaders(kTestSrcDir, KernelVersion{4, 4, 18}));
-    EXPECT_THAT(
-        match.path.string(),
-        EndsWith("src/stirling/utils/testdata/test_header_packages/linux-headers-4.14.176.tar.gz"));
+    EXPECT_THAT(match.path.string(), EndsWith(prefix + "4.14.176.tar.gz"));
   }
 
   {
     ASSERT_OK_AND_ASSIGN(PackagedLinuxHeadersSpec match,
                          FindClosestPackagedLinuxHeaders(kTestSrcDir, KernelVersion{4, 15, 10}));
-    EXPECT_THAT(
-        match.path.string(),
-        EndsWith("src/stirling/utils/testdata/test_header_packages/linux-headers-4.14.176.tar.gz"));
+    EXPECT_THAT(match.path.string(), EndsWith(prefix + "4.14.176.tar.gz"));
   }
 
   {
     ASSERT_OK_AND_ASSIGN(PackagedLinuxHeadersSpec match,
                          FindClosestPackagedLinuxHeaders(kTestSrcDir, KernelVersion{4, 18, 1}));
-    EXPECT_THAT(
-        match.path.string(),
-        EndsWith("src/stirling/utils/testdata/test_header_packages/linux-headers-4.18.20.tar.gz"));
+    EXPECT_THAT(match.path.string(), EndsWith(prefix + "4.18.20.tar.gz"));
   }
 
   {
     ASSERT_OK_AND_ASSIGN(PackagedLinuxHeadersSpec match,
                          FindClosestPackagedLinuxHeaders(kTestSrcDir, KernelVersion{5, 0, 0}));
-    EXPECT_THAT(
-        match.path.string(),
-        EndsWith("src/stirling/utils/testdata/test_header_packages/linux-headers-5.3.18.tar.gz"));
+    EXPECT_THAT(match.path.string(), EndsWith(prefix + "5.3.18.tar.gz"));
   }
 
   {
     ASSERT_OK_AND_ASSIGN(PackagedLinuxHeadersSpec match,
                          FindClosestPackagedLinuxHeaders(kTestSrcDir, KernelVersion{5, 7, 20}));
-    EXPECT_THAT(
-        match.path.string(),
-        EndsWith("src/stirling/utils/testdata/test_header_packages/linux-headers-5.3.18.tar.gz"));
+    EXPECT_THAT(match.path.string(), EndsWith(prefix + "5.3.18.tar.gz"));
   }
 }