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From: Stephen Boyd <sboyd@kernel.org>
To: Andrew Lunn <andrew@lunn.ch>, Boqun Feng <boqun.feng@gmail.com>
Cc: Jamie Cunliffe <Jamie.Cunliffe@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	rust-for-linux@vger.kernel.org, Miguel Ojeda <ojeda@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	steve.capper@arm.com, Asahi Lina <lina@asahilina.net>,
	Michael Turquette <mturquette@baylibre.com>,
	linux-clk@vger.kernel.org
Subject: Re: [PATCH v4 2/2] arm64: rust: Enable Rust support for AArch64
Date: Mon, 23 Oct 2023 17:57:59 -0700	[thread overview]
Message-ID: <d9ba6b65f70ff25df92fda4070bb58f8.sboyd@kernel.org> (raw)
In-Reply-To: <ZTLH5o0GlFBYsAHq@boqun-archlinux>

Quoting Boqun Feng (2023-10-20 11:33:10)
> On Fri, Oct 20, 2023 at 07:21:08PM +0200, Andrew Lunn wrote:
> > > +``arm64``     Maintained        Little Endian only.
> > 
> > This question is just out of curiosity, not the patchset itself.
> > 
> > What is missing to make big endian work?
> > 
> 
> FWIW, I tried the following:
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 8784284988e5..b697c2d7da68 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -227,7 +227,7 @@ config ARM64
>         select HAVE_FUNCTION_ARG_ACCESS_API
>         select MMU_GATHER_RCU_TABLE_FREE
>         select HAVE_RSEQ
> -       select HAVE_RUST if CPU_LITTLE_ENDIAN
> +       select HAVE_RUST
>         select HAVE_STACKPROTECTOR
>         select HAVE_SYSCALL_TRACEPOINTS
>         select HAVE_KPROBES
> diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> index 4562a8173e90..4621f1e00e06 100644
> --- a/arch/arm64/Makefile
> +++ b/arch/arm64/Makefile
> @@ -41,7 +41,11 @@ KBUILD_CFLAGS        += -mgeneral-regs-only  \
>  KBUILD_CFLAGS  += $(call cc-disable-warning, psabi)
>  KBUILD_AFLAGS  += $(compat_vdso)
> 
> +ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
> +KBUILD_RUSTFLAGS += --target aarch64_be-unknown-linux-gnu -C target-feature="-neon"
> +else
>  KBUILD_RUSTFLAGS += --target aarch64-unknown-none -C target-feature="-neon"
> +endif
> 
>  KBUILD_CFLAGS  += $(call cc-option,-mabi=lp64)
>  KBUILD_AFLAGS  += $(call cc-option,-mabi=lp64)
> 
> and ran the following kunit command (it will run a few tests in a qemu
> emulated VM):
> 
>         ./tools/testing/kunit/kunit.py run --make_options LLVM=1 --arch arm64 --kconfig_add CONFIG_RUST=y --kconfig_add CONFIG_CPU_BIG_ENDIAN=y
> 
> The kernel was built successfully, and all Rust related tests passed.
> 
> Of course this doesn't mean a lot, we still need people with deep
> Rust compiler knowledge to confirm whether the support is completed or
> not. But I think if people want to do experiments, the tool is there.
> 
> P.S. An unrelated topic: I found a few clk related tests (in
> drivers/clk/clk-gate_test.c IIUC) don't pass (mostly due to that the
> expected values don't handle big endian), a sample failure output:
> 
> [11:13:26]     # clk_gate_test_enable: EXPECTATION FAILED at drivers/clk/clk-gate_test.c:169
> [11:13:26]     Expected enable_val == ctx->fake_reg, but
> [11:13:26]         enable_val == 32 (0x20)
> [11:13:26]         ctx->fake_reg == 536870912 (0x20000000)
> [11:13:26] clk_unregister: unregistering prepared clock: test_gate
> [11:13:26] clk_unregister: unregistering prepared clock: test_parent
> [11:13:26] [FAILED] clk_gate_test_enable
> 
> (Cc clk folks)
> 

Thanks for the report! We should treat it as an __le32 for now. I'll
have to add tests for the big endian flag as well. Does this fix it?

---8<----
diff --git a/drivers/clk/clk-gate_test.c b/drivers/clk/clk-gate_test.c
index e136aaad48bf..c96d93b19ddf 100644
--- a/drivers/clk/clk-gate_test.c
+++ b/drivers/clk/clk-gate_test.c
@@ -131,7 +131,7 @@ struct clk_gate_test_context {
 	void __iomem *fake_mem;
 	struct clk_hw *hw;
 	struct clk_hw *parent;
-	u32 fake_reg; /* Keep at end, KASAN can detect out of bounds */
+	__le32 fake_reg; /* Keep at end, KASAN can detect out of bounds */
 };
 
 static struct clk_gate_test_context *clk_gate_test_alloc_ctx(struct kunit *test)
@@ -166,7 +166,7 @@ static void clk_gate_test_enable(struct kunit *test)
 
 	KUNIT_ASSERT_EQ(test, clk_prepare_enable(clk), 0);
 
-	KUNIT_EXPECT_EQ(test, enable_val, ctx->fake_reg);
+	KUNIT_EXPECT_EQ(test, enable_val, le32_to_cpu(ctx->fake_reg));
 	KUNIT_EXPECT_TRUE(test, clk_hw_is_enabled(hw));
 	KUNIT_EXPECT_TRUE(test, clk_hw_is_prepared(hw));
 	KUNIT_EXPECT_TRUE(test, clk_hw_is_enabled(parent));
@@ -183,10 +183,10 @@ static void clk_gate_test_disable(struct kunit *test)
 	u32 disable_val = 0;
 
 	KUNIT_ASSERT_EQ(test, clk_prepare_enable(clk), 0);
-	KUNIT_ASSERT_EQ(test, enable_val, ctx->fake_reg);
+	KUNIT_ASSERT_EQ(test, enable_val, le32_to_cpu(ctx->fake_reg));
 
 	clk_disable_unprepare(clk);
-	KUNIT_EXPECT_EQ(test, disable_val, ctx->fake_reg);
+	KUNIT_EXPECT_EQ(test, disable_val, le32_to_cpu(ctx->fake_reg));
 	KUNIT_EXPECT_FALSE(test, clk_hw_is_enabled(hw));
 	KUNIT_EXPECT_FALSE(test, clk_hw_is_prepared(hw));
 	KUNIT_EXPECT_FALSE(test, clk_hw_is_enabled(parent));
@@ -246,7 +246,7 @@ static void clk_gate_test_invert_enable(struct kunit *test)
 
 	KUNIT_ASSERT_EQ(test, clk_prepare_enable(clk), 0);
 
-	KUNIT_EXPECT_EQ(test, enable_val, ctx->fake_reg);
+	KUNIT_EXPECT_EQ(test, enable_val, le32_to_cpu(ctx->fake_reg));
 	KUNIT_EXPECT_TRUE(test, clk_hw_is_enabled(hw));
 	KUNIT_EXPECT_TRUE(test, clk_hw_is_prepared(hw));
 	KUNIT_EXPECT_TRUE(test, clk_hw_is_enabled(parent));
@@ -263,10 +263,10 @@ static void clk_gate_test_invert_disable(struct kunit *test)
 	u32 disable_val = BIT(15);
 
 	KUNIT_ASSERT_EQ(test, clk_prepare_enable(clk), 0);
-	KUNIT_ASSERT_EQ(test, enable_val, ctx->fake_reg);
+	KUNIT_ASSERT_EQ(test, enable_val, le32_to_cpu(ctx->fake_reg));
 
 	clk_disable_unprepare(clk);
-	KUNIT_EXPECT_EQ(test, disable_val, ctx->fake_reg);
+	KUNIT_EXPECT_EQ(test, disable_val, le32_to_cpu(ctx->fake_reg));
 	KUNIT_EXPECT_FALSE(test, clk_hw_is_enabled(hw));
 	KUNIT_EXPECT_FALSE(test, clk_hw_is_prepared(hw));
 	KUNIT_EXPECT_FALSE(test, clk_hw_is_enabled(parent));
@@ -290,7 +290,7 @@ static int clk_gate_test_invert_init(struct kunit *test)
 					    2000000);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
 
-	ctx->fake_reg = BIT(15); /* Default to off */
+	ctx->fake_reg = cpu_to_le32(BIT(15)); /* Default to off */
 	hw = clk_hw_register_gate_parent_hw(NULL, "test_gate", parent, 0,
 					    ctx->fake_mem, 15,
 					    CLK_GATE_SET_TO_DISABLE, NULL);
@@ -319,7 +319,7 @@ static void clk_gate_test_hiword_enable(struct kunit *test)
 
 	KUNIT_ASSERT_EQ(test, clk_prepare_enable(clk), 0);
 
-	KUNIT_EXPECT_EQ(test, enable_val, ctx->fake_reg);
+	KUNIT_EXPECT_EQ(test, enable_val, le32_to_cpu(ctx->fake_reg));
 	KUNIT_EXPECT_TRUE(test, clk_hw_is_enabled(hw));
 	KUNIT_EXPECT_TRUE(test, clk_hw_is_prepared(hw));
 	KUNIT_EXPECT_TRUE(test, clk_hw_is_enabled(parent));
@@ -336,10 +336,10 @@ static void clk_gate_test_hiword_disable(struct kunit *test)
 	u32 disable_val = BIT(9 + 16);
 
 	KUNIT_ASSERT_EQ(test, clk_prepare_enable(clk), 0);
-	KUNIT_ASSERT_EQ(test, enable_val, ctx->fake_reg);
+	KUNIT_ASSERT_EQ(test, enable_val, le32_to_cpu(ctx->fake_reg));
 
 	clk_disable_unprepare(clk);
-	KUNIT_EXPECT_EQ(test, disable_val, ctx->fake_reg);
+	KUNIT_EXPECT_EQ(test, disable_val, le32_to_cpu(ctx->fake_reg));
 	KUNIT_EXPECT_FALSE(test, clk_hw_is_enabled(hw));
 	KUNIT_EXPECT_FALSE(test, clk_hw_is_prepared(hw));
 	KUNIT_EXPECT_FALSE(test, clk_hw_is_enabled(parent));
@@ -387,7 +387,7 @@ static void clk_gate_test_is_enabled(struct kunit *test)
 	struct clk_gate_test_context *ctx;
 
 	ctx = clk_gate_test_alloc_ctx(test);
-	ctx->fake_reg = BIT(7);
+	ctx->fake_reg = cpu_to_le32(BIT(7));
 	hw = clk_hw_register_gate(NULL, "test_gate", NULL, 0, ctx->fake_mem, 7,
 				  0, NULL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, hw);
@@ -402,7 +402,7 @@ static void clk_gate_test_is_disabled(struct kunit *test)
 	struct clk_gate_test_context *ctx;
 
 	ctx = clk_gate_test_alloc_ctx(test);
-	ctx->fake_reg = BIT(4);
+	ctx->fake_reg = cpu_to_le32(BIT(4));
 	hw = clk_hw_register_gate(NULL, "test_gate", NULL, 0, ctx->fake_mem, 7,
 				  0, NULL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, hw);
@@ -417,7 +417,7 @@ static void clk_gate_test_is_enabled_inverted(struct kunit *test)
 	struct clk_gate_test_context *ctx;
 
 	ctx = clk_gate_test_alloc_ctx(test);
-	ctx->fake_reg = BIT(31);
+	ctx->fake_reg = cpu_to_le32(BIT(31));
 	hw = clk_hw_register_gate(NULL, "test_gate", NULL, 0, ctx->fake_mem, 2,
 				  CLK_GATE_SET_TO_DISABLE, NULL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, hw);
@@ -432,7 +432,7 @@ static void clk_gate_test_is_disabled_inverted(struct kunit *test)
 	struct clk_gate_test_context *ctx;
 
 	ctx = clk_gate_test_alloc_ctx(test);
-	ctx->fake_reg = BIT(29);
+	ctx->fake_reg = cpu_to_le32(BIT(29));
 	hw = clk_hw_register_gate(NULL, "test_gate", NULL, 0, ctx->fake_mem, 29,
 				  CLK_GATE_SET_TO_DISABLE, NULL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, hw);

  parent reply	other threads:[~2023-10-24  0:58 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-20 15:50 [PATCH v4 0/2] Rust enablement for AArch64 Jamie Cunliffe
2023-10-20 15:50 ` [PATCH v4 1/2] rust: Refactor the build target to allow the use of builtin targets Jamie Cunliffe
2023-10-22 10:55   ` Catalin Marinas
2023-10-22 11:07     ` Ingo Molnar
2023-10-31  0:24       ` Trevor Gross
2023-10-31 11:58         ` Catalin Marinas
2023-10-31 19:01           ` Trevor Gross
2023-12-12 16:47           ` Will Deacon
2024-01-22  9:17   ` Trevor Gross
2024-01-25  3:19     ` WANG Rui
2024-01-26 19:37       ` Masahiro Yamada
2024-01-27  5:08         ` WANG Rui
2024-01-27 17:31           ` Miguel Ojeda
2024-01-22  9:29   ` Alice Ryhl
2024-01-24  9:12   ` Masahiro Yamada
2023-10-20 15:50 ` [PATCH v4 2/2] arm64: rust: Enable Rust support for AArch64 Jamie Cunliffe
2023-10-20 16:45   ` Catalin Marinas
2023-10-21 13:40     ` Miguel Ojeda
2023-10-22 10:48       ` Catalin Marinas
2023-10-22 12:14         ` Miguel Ojeda
2023-10-20 17:21   ` Andrew Lunn
2023-10-20 18:33     ` Boqun Feng
2023-10-20 18:47       ` Andrew Lunn
2023-10-21 12:50       ` Alice Ryhl
2023-10-21 13:41       ` Miguel Ojeda
2023-10-21 16:03         ` Andrew Lunn
2023-10-22 12:57           ` Miguel Ojeda
2023-10-24  0:57       ` Stephen Boyd [this message]
2023-10-25 23:55         ` Boqun Feng
2023-11-01 15:04       ` Linus Walleij
2023-10-31 18:31   ` Matthew Maurer
2023-11-28 18:29     ` Boqun Feng
2023-12-13 19:00     ` Miguel Ojeda
2024-01-22  2:01   ` Fabien Parent
2024-01-22  5:27   ` Behme Dirk (CM/ESO2)
2024-01-22  9:30   ` Alice Ryhl
2024-02-09 17:38 ` [PATCH v4 0/2] Rust enablement " Catalin Marinas
2024-02-09 21:41   ` Miguel Ojeda
  -- strict thread matches above, loose matches on Subject: below --
2023-10-24 14:17 [PATCH v4 2/2] arm64: rust: Enable Rust support " Pratham Patel
2023-10-24 15:19 ` Miguel Ojeda
2023-10-25  2:01   ` Pratham Patel

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