arch: riscv: support CONFIG_USERSPACE in CONFIG_RISCV_CURRENT_VIA_GP (033804e2) · Commits · Wenxi XU / zephyr

arch/riscv/Kconfig

+1 −1

Original line number	Diff line number	Diff line
		@@ -30,7 +30,7 @@ config RISCV_GP

		config RISCV_CURRENT_VIA_GP
		bool "Store current thread into the global pointer (GP) register"
		depends on !RISCV_GP && !USERSPACE
		depends on !RISCV_GP
		depends on MP_MAX_NUM_CPUS > 1
		select ARCH_HAS_CUSTOM_CURRENT_IMPL
		help

arch/riscv/core/isr.S

+3 −1

Original line number	Diff line number	Diff line
		@@ -169,7 +169,9 @@ SECTION_FUNC(exception.entry, _isr_wrapper)
		.option norelax
		la gp, __global_pointer$
		.option pop
		#endif /* CONFIG_RISCV_GP */
		#elif defined(CONFIG_RISCV_CURRENT_VIA_GP)
		lr gp, ___cpu_t_current_OFFSET(s0)
		#endif /* CONFIG_RISCV_GP / CONFIG_RISCV_CURRENT_VIA_GP */

		/* Clear our per-thread usermode flag */
		lui t0, %tprel_hi(is_user_mode)

tests/arch/riscv/userspace/riscv_gp/prj.conf

+0 −1

Original line number	Diff line number	Diff line
		CONFIG_ZTEST=y
		CONFIG_RISCV_GP=y
		CONFIG_TEST_USERSPACE=y

tests/arch/riscv/userspace/riscv_gp/src/main.c

+42 −2

Original line number	Diff line number	Diff line
		@@ -10,6 +10,10 @@
		#include <zephyr/kernel.h>
		#include <zephyr/ztest.h>

		#if !defined(CONFIG_RISCV_GP) && !defined(CONFIG_RISCV_CURRENT_VIA_GP)
		#error "CONFIG_RISCV_GP or CONFIG_RISCV_CURRENT_VIA_GP must be enabled for this test"
		#endif

		#define ROGUE_USER_STACK_SZ 2048

		static struct k_thread rogue_user_thread;
		@@ -18,22 +22,58 @@ static K_THREAD_STACK_DEFINE(rogue_user_stack, ROGUE_USER_STACK_SZ);
		static void rogue_user_fn(void p1, void p2, void *p3)
		{
		zassert_true(k_is_user_context());
		uintptr_t gp_val = reg_read(gp);
		uintptr_t gp_test_val;

		/* Make sure that `gp` is as expected */
		if (IS_ENABLED(CONFIG_RISCV_GP)) {
		__asm__ volatile("la %0, __global_pointer$" : "=r" (gp_test_val));
		} else { /* CONFIG_RISCV_CURRENT_VIA_GP */
		gp_test_val = (uintptr_t)k_current_get();
		}

		/* Corrupt `gp` reg */
		reg_write(gp, 0xbad);

		/* Make sure that `gp` is corrupted */
		if (IS_ENABLED(CONFIG_RISCV_GP)) {
		zassert_equal(reg_read(gp), 0xbad);
		} else { /* CONFIG_RISCV_CURRENT_VIA_GP */
		zassert_equal((uintptr_t)arch_current_thread(), 0xbad);
		}

		/* Sleep to force a context switch, which will sanitize `gp` */
		k_msleep(50);

		/* Make sure that `gp` is sane again */
		if (IS_ENABLED(CONFIG_RISCV_GP)) {
		__asm__ volatile("la %0, __global_pointer$" : "=r" (gp_test_val));
		} else { /* CONFIG_RISCV_CURRENT_VIA_GP */
		gp_test_val = (uintptr_t)k_current_get();
		}

		zassert_equal(gp_val, gp_test_val);
		}

		ZTEST_USER(riscv_gp, test_gp_value)
		{
		uintptr_t gp_val = reg_read(gp);
		uintptr_t gp_test_val;
		k_tid_t th;

		zassert_not_equal(gp_val, 0);
		if (IS_ENABLED(CONFIG_RISCV_GP)) {
		__asm__ volatile("la %0, __global_pointer$" : "=r" (gp_test_val));
		} else { /* CONFIG_RISCV_CURRENT_VIA_GP */
		gp_test_val = (uintptr_t)k_current_get();
		}
		zassert_equal(gp_val, gp_test_val);

		/* Create and run a rogue thread to corrupt the `gp` */
		th = k_thread_create(&rogue_user_thread, rogue_user_stack, ROGUE_USER_STACK_SZ,
		rogue_user_fn, NULL, NULL, NULL, -1, K_USER, K_NO_WAIT);
		zassert_ok(k_thread_join(th, K_FOREVER));

		/* Make sure that `gp` is the same as before a rogue thread was executed */
		zassert_equal(reg_read(gp), gp_val, "`gp` corrupted by user thread");
		}

tests/arch/riscv/userspace/riscv_gp/testcase.yaml

+9 −2

Original line number	Diff line number	Diff line
		@@ -3,6 +3,13 @@ common:
		ignore_qemu_crash: true
		tags: kernel riscv
		platform_allow:
		- qemu_riscv64
		- qemu_riscv64/qemu_virt_riscv64/smp
		tests:
		arch.riscv64.riscv_gp: {}
		arch.riscv64.riscv_gp.relative_addressing:
		extra_configs:
		- CONFIG_RISCV_GP=y
		- CONFIG_RISCV_CURRENT_VIA_GP=n
		arch.riscv64.riscv_gp.thread_pointer:
		extra_configs:
		- CONFIG_RISCV_CURRENT_VIA_GP=y
		- CONFIG_RISCV_GP=n

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